Last year, I wrote a lengthly post about why its so necessary to drink more water. Drinking water isn't really a problem for me, its simply remembering to drink it.
I discovered that if you simply always have a bottle of water on your desk, or within reach of where you work, it will require nothing more than the thought "I could use some water" to grab your water bottle and drink some water (maybe even leave the cap off!). But if you have to get up and walk somewhere just to get some water, you're a lot less likely to do it.
I like to buy a single 1.5 liter Poland Spring bottle of water and simply make sure I refill it once during the day. That means I'll get at least 100oz of water per day. At the end of the week, I toss out the bottle and buy a new one (reusing the bottle too many times can eventually cause toxins in the plastic to release into the water).