First, before you get there. If you're applying for a seat, especially if it's a by-election make sure your social media is thoroughly cleaned up before you've announced you're in the running. As soon as your name appears anywhere in connection to the seat, whether as a possible contender or a long listed candidate, there will be someone from a certain sewer-dwelling website going through your feeds looking for stinky stuff. In fact, don't wait until then. Sort it now.
Okay, well done, you've won your election and you're off to the Commons. All of a sudden you're expected to be an advocate, a lobbyist, a leader, a tribune, an example, and an office manager more or less from day one. Oh yes, and you don't have much power either. Did no one tell you that? But you do have a pretty hefty salary. Your first decision is what you're going to do with it. You can trouser the lot, but that's not recommended. Nor is doing the workers-MP-on-a-workers-wage schtick if you don't want ostracising, which isn't good for getting stuff done on behalf of the people you're representing. So, once the PLP has taken its share (ah, you weren't told about that either), and with plenty left over a yearly donation to CLP/branch funds is a must, whether the local party is cash strapped or not. Also, during this Parliament Ruth Smeeth was one of the few MPs to refuse the 10% pay rise and instead used that cash to fund charitable causes in her Stoke North and Kidsgrove constituency. Doing that or something similar is the right thing to do, and has the happy consequence of paying itself back many times over in goodwill.
That's the easy bit. Then comes sorting out your staffing. The first rule here is do not employ your family. Conservative MPs are buggers for doing this. Nearly every Tory MP whose office arrangements I know something about employ otherwise unemployable husbands and wives and sons and daughters. All at the top of IPSA pay scales, funnily enough. Also, they tend not to get too much heat from the media for it. As you're Labour, if you're daft and go down this route there's a much greater chance you'll cop for it. So don't. Second, it is absolutely crucial you have two operations, regardless of whether you represent a London constituency or not. You need parliamentary staff (one usually suffices when you're a backbencher) and staff in a constituency office. And this is more than just a matter of division of labour.
Your parliamentary assistant is useful for briefing notes, speeches, popping down to the Commons library, tours for constituents, babysitting guests and a thousand and one other things. Just don't get them washing your laundry or driving round London doing your shopping. That. Is. Not. What. They're. For. There is another, understated advantage for having permanent parliamentary staff. They will hang around and socialise with other bag carriers. This is good, so make sure you hire someone gregarious. Because they can do a lot of networking for you. If you're interested in making a splash in a particular policy area, a good staffer will have a working knowledge of what their mates are working on and might suggest meetings with such-and-such MP looking into something similar. That's the good, noble reason. Then there's gossip. You might have gathered by now, politics loves gossip and Westminster is full of it. Having a staffer helps keep you abreast of what's going on where indiscretions are rife and nothing stays under wraps for long. As much as you might dislike this sort of thing, you've got to have eyes and ears working for you.
Constituency staff are slightly different but no less important. Unless you're from the the Paul Nuttall school of lazy arses, you're going to be in Parliament most of the time, so your constituency staff will be the primary means by which the constituency and the members interact with you. So choose wisely. You don't want staff watching Jeremy Kyle all day instead of doing work. You don't want anyone taking a haughty attitude to members, and you certainly don't want employees causing embarrassment by inappropriately using your constituency property when you're not around. My recommendations would be two or three staff who don't necessarily share your brand of Labourist politics, which is good for advice/speaking truth to power. So go on, hire a Progress member and a Corbynist. Make sure you take on people with good writing and communication skills - they will be making representations on your behalf to ministers and sending things to constituents in your name. Preferably, hire people who live in or will move into your constituency and so know what it's like living there. And, this cannot be emphasised enough, employ party members. Membership is no guarantee of good judgement, but party members more likely have an eye for bits and bobs of casework that have local and national party political ramifications. Also, as members in the local party they straight away strengthen your base and will likely build close relationships with councillors and key local activists. The gossip function applies here too. Staff, however, aren't robots. Turn over is quite high, partly because there is no career progression. So give them autonomy. Allow them to fill their notebooks with contacts, to go on visits to local employers, public bodies, charities, etc. Give them projects to do and goals to work towards. Don't be an overbearing boss, don't micromanage and ensure you don't employ anyone as office manager with that kind of attitude. If you treat them well, take them seriously, listen to them, you will have their loyalty and support beyond the terms of employment.
On your relationship to your constituency party, take it very seriously. Only fools don't believe the CLP is the boss. Remember, you're only going to Westminster because the Labour badge was against your name. So be hands on, but not too hands on. Make sure you turn up to constituency meetings and give your report. If you're invited to a local party event, make sure you're there much more than not. Go out for drinks with members after meetings. Organise affordable socials and muck in. Even accept the odd dinner invite, and not just with the nice middle class professionals who want to show you their bookshelves. Have time for people, don't give politicians' answers in meetings, and listen. One thing you'll find are lots of irritating members like me: people wanting to tell you how to do your job. Take the time to respond as the one thing you want to avoid is a reputation for having a tin ear. And if you haven't got it, you're going to have to dig deep wells of patience - there's no way round it. At the same time, don't be afraid to push your politics. The sad fact is the best place to go to avoid talking politics is a Labour Party meeting, so change that, politicise things, work to persuade members of the merits of your views. Also, be very clear and provide a political rationale for the two or three priorities/hobby horses you have and update folks on any progress made. The members chose you and are invested in your success, so make them feel part of it.
While we're talking constituencies, you simply must be all over yours like a rash. Good staff can cover for your absence some of the time, but you should lead from the front. This is doubly important in marginal seats, for obvious reasons, but also "stronghold" working class seats like Stoke Central to break the cycle of disenchantment and disengagement. Do the bulk of your surgeries. Make sure you or a staff member attends stuff you're invited to. Make sure you have an extremely good relationship with local unions and do what local members ask. Keep an eye on new businesses opening up and get in touch to offer support. Work to bring people together around common interests and projects. Build a good working relationship with the local authority, whether Labour-run or not, but do not be afraid to take them to task or go to war with them when necessary. And campaign hard by helping out local councillors, running your own doorknocking/leafleting sessions, and supporting local Labour Group priorities. Show you're an attentive, dynamic MP by putting yourself out there.
Last of all, remember you're a member of the PLP. You're in a privileged position, but that doesn't grant you a privileged point of view. You may be clever, be a good organiser, possess a silver tongue, great charisma, or an unaffected manner, but you're no better, smarter, or savvier than the great bulk of Labour activists. Luckier, maybe. Do bear that in mind as your brain starts playing host to the parliamentary ways of doing things. As an opposition MP, your powerlessness will be reinforced every time the Tories push through legislation that attacks our people. As you dwell inside a media bubble, all of a sudden things that barely registered when you were a civilian loom large in yours and others' imaginations. Both of these work together into a commonsense in which Parliament and getting power is the be-all and end-all, and that will work to distort your view of the world. Hence why you need good staff and good relations with your constituency party, these people can anchor you.
The second thing to remember is what politics is about. It's the interests, stupid. The Labour Party is the political expression of the labour movement, and was founded by the organised working class and the progressive middle class to prosecute their interests. Arguably, its failure to do so is the root of the party's present malaise. The story is the same in France, where too many of our people have been abandoned to the fascists, and in Italy. Your job as a Labour Party activist who happens to be a MP is to follow those interests through. The boarding school/pressure cooker environment can engender the feeling of all MPs being in it together, regardless of party. You start feeling that way you need to shut that shit down. Go ahead, pursue friendly, congenial relations with politicians from other parties, but never forget they're means to an end to get your way - the party's way. Because they will be doing exactly the same to you. Remember, it's only Labour that think the party's there for the common good, the Tories aren't naive enough to entertain such a delusion.