When you are following a tapestry crochet chart, you have rows or rounds to follow and color color changes. You can mark the rounds/rows you already worked with a pen or pencil, but if you are working on a pattern that repeats itself several times or if you intend to make the same item again, you would have to print out another copy, so I have a couple of times for you.
Tip 1: use post it to cover the rows/rounds you have already worked on. Just take it off and move it. Easy peasy, right?
Tip 2: Magma pattern holder by Knitter's Pride! Oh this is my favorite thing, I was tickled pink when I found this at my local yarn shop. This is a magnetic folder, you place your paper, secure it with the magnets that it comes with and then you follow your pattern with the magnetic "ruler". This not only works perfectly for chart, but it is great for following written patterns, too!