A "first look" deal is a deal between a producer or writer-producer and a studio or network that stipulates, essentially, that in exchange for a certain sum of money, the producer or writer-producer guarantees the counter-party (in this case, the studio or network) that they’ll have dibs – or "first look" – on any project or script that the other side comes up with.   What it doesn’t specify, of course, is what a "look" is, or what "first" means...