Tips for Easy Grouting
It is important before beginning to grout, that you prepare the area first. To have good full grout joints, one needs to remove all thinset or mastic that has come too far to the surface in the joints. Using a utility knife works well. Be careful not to allow the knife to jump out of the grout joint and scratch the tile.
After thoroughly cleaning the joints, vacuum them well and make sure all dust and debris is clear of the area. After the area is clean, you need to make sure any adjacent areas that you want to keep clean are able to have the grout cleaned off of. For example if you are grouting up to stainless steel, you don't need to protect it. However, if you are grouting up to certain types of wallpaper, it would be a good idea to mask off the area so it doesn't get residue on it.
Spreading the Grout
Once the area is ready, you need to mix the grout properly. If you have a large area, make sure you maintain consistency of grout and water amounts so the color and shading won't vary between batches. Decide how much grouting you can do before it sets too hard. A 10' x 10' floor area or a whole tub surround may be a good beginning amount. Using the table on the bag, mix the amount needed for the area, given your tile size and grout joint width.
When you have the grout mixed, let it slake (wait 10 min.) and then remix. When ready, take your grout float and work the grout into the joints by covering the entire tile and pushing the grout into the joints with pressure. After applying the grout and you know the joints are full, take the float and remove the excess diagonally from the tile joints. Keep doing this until all the joints are full of grout.
Cleaning the Grout
After the grout is spread, wait for a few minutes to up to 20 minutes depending on temperature and humidity. You need to wait for the grout to harden up a bit before initially cleaning it. When the grout has hardened an little, take a wet, clean, rounded corner sponge and wipe the grout off the tile surface. Use a "flip-wipe" method. This means that when you wipe the tile, flip the sponge and use the opposite side. When both sides have been used once, clean the sponge and repeat. Do this over the entire area until all the excess grout is removed from the tile. If necessary, after this is done and it sets again for awhile, it may be a good idea to repeat these steps after another hour. When it is dry, take a terry cloth and wipe the dust off the tile.
Then, you're done!