Thought you were doing the walls, you'll not need a battern then.
If you're doing the floor, start in the middle and not against a wall (It may not be parallel/perpendicular to the others).
You've got to start by balancing out your first placement so if the walls aren't parrallel to each other then work out a line inbetween these two so when you reach cabinets and walls etc they'll look ok.
A good idea to place them on the floor without the adhesive to check the layout first.
Don't tile onto floorboards, you'll need a plywood base first or the grout will crack.
Tiling on concrete is okay.
Tiling walls
If you're doing a wall then fix a horizontal wooden battern across temporarily to support the first row of tiles.
Start approximately in the middle of the wall ( width ways ) and near the bottom vertically.
Plan where you put the first tile so when you reach the wall and floor/ceiling you won't be left fitting a very thin tile which doesn't look good.
Use the cross shaped tile spacers, put two in at each side of the tile. (At 90 deg to the wall ,vertical and horizontal edges), you pull them out when the adhesive has set.
Don't put them at the intersecting corners and don't leave them in.
Apply the adhesive to the wall and then pull the comb across to achieve the correct thickness, only do a small area at a time.
When you come to the joint at the next wall, use silicone and not grout because it's likely to crack.