When it comes to being a dev it really is a case of who you know. One of the most important things you can do is get face time with as many people as possible. Remember to practice the pitch like I mentioned in a previous post and head out to places like E3, GDC, SXSW, and any other gaming related convention you can manage. Remember to print out as many business cards as you can, there are plenty of sites out there that will do 1,000 cards for a 5$ introductory offer or sometimes less, my suggestion is design a good card and then make as many as you can, they go faster than you think. Hand one out to almost every person you talk to as you never know who's going to actually help. Feel free to find the big reps but don't hold out your hopes they like to waste time, they'll hear you out and sound interested but the chances of them actually picking up your game are slim, though at least the chance is still there which makes it all worth while.
Whatever you do don't sign any contracts without seriously reviewing them first. Some of the best sounding news can easily be a trap if you're not careful. Just because the contract says they've signed you for multiple games doesn't mean they've agreed to fund you or that they will publish them. It simply means they hold the rights to your sequel which means if you make a second game they get to say whether or not you can even sell it basically. This can kill your franchise fantasies before they've even started.
While you're at all these conventions it's also suggested you bring a notepad and a few pens and take a lot of notes. You'll probably also be using it for adding ideas to your game or making tweaks as well as addressing issues you hadn't considered. I say pens because pencils will require constant sharpening and easily break making them unreliable for the environment you're in. You'll be needing something that works constantly and quickly, I actually went through 6 notepads at my last GDC and 2 pens. I've found some good gel pens though that last surprisingly well, got them at staples with my notepads and I love them.
You'll find that your pitch will almost hone itself once you say it enough times you'll just realize what details are easy enough to omit without losing the core of the game idea. Though I will suggest that you avoid any direct comparisons to existing games unless you're extremely specific. You shouldn't say "it's like halo meets gears of war" but you might get away with saying "if gears of war had plasma shields and warthogs in a larger environment" though even in that case it's coming off as almost a carbon copy of gears which it probably isn't, what you're meaning to talk about is a fast paced gritty third person sci-fi shooter. As opposed to a slow paced one like dead space which is really equal parts survival horror and shooter.
Just remember you're trying to talk to as many people as possible and get their interest peaked without telling them every detail of the game, if they're serious about it they'll call you that's what the cards are for. As to the cards themselves you should include your cell phone, home phone, primary email, and any other contact info you might want to provide. Try to make the card unique so it doesn't get buried in the crowd, in particular if you have any screenshots or concept art for your idea try to put it on the card somewhere or as the whole background, though if you go that route make sure they can still clearly read the text for your contact info. No card gets dismissed quicker than the one where they have to take a second to find a way to read the info. If the card company you use allows it I would even suggest on the back you also print your game pitch again, keep it small as a tweet and you should do fine.
Putting all these things together you establish yourself as a name to be recognized and not forgotten, which may prove useful down the line even if it doesn't help you in the now.