Oh, sorry, I dunno what happened to the rest of my post there...
No, I'm not a handicapper. There aren't many books that keep their own dedicated handicapper on staff anymore, not since the advent of the internet and availability of so much more information. That said, anyone worth their salt in this industry will do a little bit of handicapping when needed, and a general understanding of probabilities and statistics is necessary. Not so much for making up lines but for figuring out what a given team's odds to win something should be, for example. It's always good to have an idea if the odds you're giving out are at least roughly what they ought to be, instead of just blindly following the rest of the industry.
As for what I do - I sit in front of six computer screens, each with various functions. One is my workstation, from which I move lines, take bets, set up new games, grade existing games, etc. Another is an identical workstation for my co-worker, who does much the same as I do.
More on that:
All told there are three of us main managers and another five sub-managers. Between us we cover 6am - 1am, 7 days a week. Two of the sub-managers' main job is to stay late and grade the remaining games in the schedule. The main managers pretty much never work past the start of the last game of the night. For really important/busy times, like college football or basketball Saturdays, with their huge slate of games, or NFL Sundays, two main managers work together to keep up with everything that's going on. At less busy times, it's usually a main manager with a sub-manager, because it's a waste to have two strong people working with not much to do.
So yeah, a co-worker and I sit at a long desk, each with a workstation, with another four computers between us. Those computers are for running the various line-tracking programs that let us compare our lines against everyone else's, and keep us up to date on line trends, injuries, suspensions, and so forth. We also have a program that shows us all the bets coming in from the floor (clerks taking calls) and the internet, and a program showing us line moves within our office (there are triggers that can be attached to people's accounts to automatically move the line, depending on what sports they're good at).
So yeah, that's what I do. I watch the bets come in, move the line accordingly, or move it back if necessary. I try to balance the book as much as possible, unless we have info one way or the other, in which case we try to attract more action on the side less likely to win, according to our information. When not doing these things I set up upcoming games, grade (put the scores in) games that are over, put up lines on halftimes, etc. When not doing that stuff, I'm posting here.