My dd is almost a year and I occassionally bring her to work w/ me all day.
1-I baby proofed my office
2-brought a couple of her toys, but she only plays w/ them for short periods
3-because of #2, I gather items for her to play w/ at work that aren't hazards, such as box lids (she likes to crawl in and out of, unconnected keyboard and mouse (loves to play w/) and rattles made of small boxes (have them taped because dd has figured out how to open them).
4-I bring her favorite snacks, such as Cherrios, apples, bananas.
5-I either bring a pack-n-play pen or a stroller so she can sleep
6-I also bring a sling or backpack carrier depending on what I am doing that day.
7-I bring all the other necessities for baby
When I have her in the office, I just work and usually she will entertain herself for a while. Then, about every 30 min, she will want mommy attention (either holding her while giving the bottle - this allows me to work), talking to her while she is cruising around my chair/desk or even playing w/ her (I'll put all my papers on the floor and work while she cruises around me to play w/ my hair or climbs over my legs)
It isn't easy, but you will definately get into a routine and figure out what works best. Good Luck,