1. Bigger isn't necessarily better, but it's definitely easier. Larger tiles are much easier to install than small ones. Larger tiles are commonly used for bathroom walls, but are great for kitchens and other rooms too. The smaller 1x1s are going to take longer to set, so choose a small pattern.
2. What you can't see, will hurt you. If you don't have a flat subfloor, you won't have a successful install. Self-leveling subfloor compound works great and is easy for a DIYer to install. Other options are plywood or cement backer board, but regardless of what is used, the subfloor should be at least 1" thick to ensure a quality job.
3. Squaring a room is as easy as 3-4-5. The best method to squaring a room is using a 3-4-5 triangle. Measure 3 feet against one wall, 4 feet to the center of the room and connect the two lines to make a triangle with a 5 foot line. If the room is larger, use 6, 8 and 10-foot lines. If it's smaller, use 18", 24" and 30". Mark off all lines by snapping a chalk line along the measurements.
4. Make the best of a sticky situation. Thin-set not only keeps tiles on the floor, it can make up for minor imperfections in the subfloor. There are different thin-sets for each application of tile, but for ceramic tile, use a latex modified thin-set. Latex modified thin-set only needs water. Remember, only mix what can be spread or used in an hour, otherwise, the job will become very hard. There is also a premixed thin-set which would be better for wall tiles. It is stickier and the tiles won't move much. With thin-set, you can always add a little more on one side if the subfloor isn't perfectly level or take away a little on the other side to straighten the subfloor.
5. If cutting corners, rent a wet saw. Renting one will save time and frustration. Unless it's a perfect house with perfect rooms, you will have to cut the tiles. The time saved in cutting all of the tiles perfectly will pay off immediately. Wet saws are relatively inexpensive and can usually be picked up in any home supply store.
6. Don't rush yourself into a poor job. Always take your time and work in a small area to ensure you get everything right. Behind every quality tile job is an installer that chose to take his time. Even when working in a small area, don't rush to lay the tiles down.
7. When the trowel gets jammed, butter the tiles. When working in tight corners or edges, the trowel won't be able to fit inside that space. The easiest way to work around this problem is to put the adhesive on the back of the tiles.
8. Don't rush the cure. Even though all the tiles are down on the floor and set, don't start putting the grout down. Allow the thin-set the proper amount of time to dry, otherwise you will damage the tiling job.
9. Never trowel grout in a straight line. There are two types of grout, wall and floor grout. The only difference is that floor grout has sand in it and wall grout doesn't. Make sure the grout is the right consistency, and trowel it diagonally to ensure an even application.
10. Guarantee perfect gaps with plastic spacers. Buy the space between each of the tiles in a bag. Plastic spacers come in different sizes for different sized tiles. Simply place the little X's between the tiles while they set and remove them before grouting. This will ensure the same exact space between each tile.
Seal before tiling. Always waterproof showers and wet areas before tiling them. Tile installations do not act as a 100 percent moisture barrier. They are designed to protect the waterproof surface below them and make cleaning easier. There is a good range of waterproofing materials available that are easy to apply and work well.
Save the extra tiles. Keep spares for any future repairs. Ceramic tile is very brittle and if a heavy object falls on the tile, chances are it's going to break.