You can tile one half one day and one half the next no problem. Just wash your buckets out well and mak sure your tools are clean at the end of each day.
Be sure to scrape up any adhesive you're not using at the end of the first day as even little bits next to the already fixed tiles will stop you pushing the newer tiles up to them the next day.
Ensure you're mixing your tiles from their boxes as you lay them because if you don't and a box is a slightly off shade and you don't spot it till you grout it you'll end up with a patchy floor.
Discussions on all aspects of tiling & installing tiles in the tiling forum.
Tile over 2 days? 
Linear Mode
