A: Hey, Tile Dave. A tile backsplash is certainly a doable project I'd rate as a 5 out of 10, but there are some sticking points where things can get away from you if you're not prepped. So here's a semi-organized version of what pours through my mind when you say tile backsplash:

Level Lines. Use a good level and strike level lines all the way across the wall so that you can use the line as a guide for laying up your tile. Most levels work, but I've been using Irwin's deluxe box beam levels lately and I like 'em! Also, measure level as it corresponds to your new counter and cabinets (which should, but may not be, totally level and parallel). Worst case, you may have to make a decision about the line on which you run the tiles. This could take some experimenting to see which line looks level versus which one is level. All this is called "layout."

Equal "Reveals." You want the tiles centered in the "field" of the wall. In other words, you want the tiles on the left and right ends of the back splash to be the same size. If you can dig up a Carpenter's Notebook, I explain that technique in good detail. You might also want to do it in the up and down orientation too but not necessarily. Usually, starting the tile install from a plumb layout line in the center of the wall, then working left, then right, takes care of this.

Notching. Tile butted up to a window trim that is not significantly proud of (or thicker than) the tile looks bad to me. There is a very visible transition there that is difficult to hide. You may want to strip the window apron (the trim below the sill) and replace it after the tile is up or install a different one to prevent this. This is an important detail to work out before you have a bucket full of thin-set drying on the counter.

Switch Boxes/Electrical Devices. You'll have to cut out for switch boxes, which can be tricky. A tool like the RotoZip with a tile-cutting bit can really help here. Another tool that works for this is the Rockwell SoniCrafter. Pro tile guys use a plier-esque tool called nibblers which I have had little luck with (I usually end up cracking the entire tile: fury). That said, there's room for a little error because the switch plate covers the rough cut out. Also, you have to bring your receptacles out to the level of the tile for the switch plates to work right, usually not a problem. Be careful around the electrical.

Mesh Backing. The mesh backing means you can set more tiles at once, but the thing to watch out for is that the mesh can pretty easily deform while you press and twist the tiles into the thin-set. The result is that within a single square foot the line can get out of true. If you don't press them into the thin-set uniformly they look lumpy -- keep an eye peeled for this as you set sheets.

Furthermore, cutting these tiles on a manual tile saw is a mega-chafe. Cutting on a wet saw -- mine is a primo Porter-Cable unit is much easier.

Protecting The Countertop . I would get some big pieces of cardboard and blue-tape them to the counter (including around the front) to prevent filth and muck and scratches which can be a result of everything from tools to your belt buckle.

Tools and Supplies. You need some good buckets (I use a flat-bottomed, two gallon bucket that I believe you can buy in the paint department of The Home Depot) to mix up thin-set, a notched trowel to apply it, a grout sponge for (duh) grout. I use what's called a margin trowel to mix, scoop and otherwise fling thin-set onto the wall. Then there's one or two sponge floats you'll need for grouting and a bag of cotton rags for wiping off the grout residue. Clean the bucket after every mix-up to prevent dried stuff from getting into the new batch.

Sealing the Tile. After the grout is on and wiped clean, I would apply a sealer to really protect it.

Caulk Versus Grout. Instead of grouting the joint between the cabinets and wood trim and tile and counter and tiles, it's best to use a high quality, color-matched latex caulk. Reason: the cabinets will, albeit slightly, move with temperature and humidity changes. Grout doesn't and the joint can crack. So this means you need to run a smooth, clean caulk bead for it to look good.

I might be overthinking this, but at least it'll give you some guidelines so you get the results you want.

Good luck.