One of the easiest kitchen makeovers you can do is install a tile backsplash. Installing tile on the wall between the countertop and the upper cabinets allows you to customize the look of your kitchen and add patterns or colors that compliment the rest of your house. It also makes cleanup easier as you no longer have to scrub the wall but just wipe down the tile while cleaning the counters.
You can adhere the tiles to existing wall board, formica, or plaster but be sure to clean all surfaces thoroughly and even sandpaper them before applying adhesive.
If you’ve got old (retro) tile as above and want to replace it you can attempt to separate it from the wall but many times the tile is permanently stuck to the wall board and in that case it’s easier to just cut out the wall board and replace it, then tile onto the new wall.