This is a response to Lisa's comment below. She's got a trainee place as a planner and she's looking for advice. I've been a bit slow about this. Sorry.
Here are some random thoughts from me, hopefully other people will add theirs. I'm hoping so because I'm not sure I'll be able to come up with anything non-obvious.
Firstly, be pleased and proud. There aren't a lot of trainee planners around and you're right I don't think people will know what to do with you. But you've done dead well to get hired, so you must have something special about you.
1. Generate enthusiasm
Planner's are mostly aspiring academics and/or intellectuals. So they're often tempted to do the cool brainy thing; all knowing cynicism and ironic detatchment. Don't be drawn in. Not many can get away with it, and it annoys the hell out of your colleagues, who'll be tempted to hate you anyway because you don't appear to have a real job.
Be enthusiastic, positive and optimistic. Do a lot of offfering to help, you won't get taken up on it a lot because it's often too much trouble to brief someone than to do it yourself. But you should offer.
2. Make friends
The obvious thing to do is suck up to all sorts of senior people and if you can make friends with impressive senior people then great, but you probably won't see enough of them to do that. So make friends with everyone you can.
Hang out with that junior creative team who no-one seems to have any time for, or that regional account person who everyone ignores. a) they've got stuff to teach you and they'll probably take the time to do it (senior people won't take time to train you and they can't remember how they did all the basic stuff anyway) b) they won't be junior forever.
It's especially important to make friends with all the people who actually get stuff done; admins, production, traffic, travel, TV, IT. A lot of your first year will be about getting documents made, or videos or stuff, you probably won't be making lots of ads or meeting lots of clients. So you need to get the agency machine working on your behalf. You need to know how to get things photocopied when the photocopiers are all broken. Or how to make that presentation you've got to do to your planning director look really cool. Don't dismiss these things as trivial or beneath you. Most of agency life is execution not strategy, you need to know how to get things done.
3. Collect ideas
You should be trying to build a personal portfolio - not just the things you've worked on, but the things you've thought of, the things you've noticed. Make sure you notice and collect everything that happens. And, make sure you collect your own opinions. Look at all the ads your agency makes, work out what you think of them, have an opinion on them. Be ready to talk about that. You should probably get yourself ready to have opinions on everything. Whether you stay where you are, or whether you move, you're going to have to get used to talking about communications and offering an opinion - so start practicing.
4. Read And Watch
You should be devouring all kinds of books and thinking about brands right now. All the usual suspects. Adam Morgan. Malcolm Gladwell. All the APG books. Mark Earls. Jon Steel. All them.
But the more interesting and useful stuff will be the documents and presentations that the people in the agency generate.
Because they'll be generating stuff about subjects that are too small for anyone to write books about. Fishfingers and Buses and Yellow Fats and Consumer Perceptions Of Interest-Rate Led Advertising.
This stuff is going be your trade so you need to start finding out what it looks and smells like. And you need to work out what's good and what's bad. Read every document you can get hold of, go to every presentation they'll let you attend. Steal from the good stuff, work out why the bad stuff's bad. Start to develop a personal presentational style before you get infected too much with plannerly-ness.
5. I've run out of steam.
Anyone got anything else?