Hi PJ
It's easy, measure the room TWO TIMES to find the middle of the room.
Draw an + on the floor, thats your start point.
Lay the tiles from the center outwards - remember to work backwards to the door!!!
Only lay the grout (sp?) - max' 1m sq, and use a level. If it's not level take the tiles up and dump the grout and start again...
If it is the kitchen - tell your wife/partner to find a good takeaway!