Tips and Tricks to make cross stitching large projects easier:
1. Use a hoop. If you keep one hand above the fabric to push the needle through and another below the fabric to catch the needle and push it back you won't have to crumple one side of the piece to hold on to it. Just drape the fabric over your lap like a blanket.
2. With large pieces that take a long time (e.g. years) to complete, care must be taken to ensure that the fabric does not become soiled from handling. Wash your hands before starting your project every time, especially if they are greasy or smelly. (You don't want your project to smell like chopped onions, do you?) Embroidery can be cleaned, but you can never be sure that the colours in the floss won't run so avoid it if possible.
3. Buy all the floss at once if you can. It's really annoying to have to stitch all the same colour for months on end, so you might flit around the project a little, doing different coloured blocks for variety. Wind the skeins of floss onto bobbins (label these with colour numbers) and keep them in a box. Keep a sheet of paper in the floss box to write down the numbers of any colours you have run out of and require more so that the next time you're going to the sewing shop you can just grab the list and go. Have a couple of extra needles too...they're easy to lose in the carpet.
4. If the pattern is very large, or if the symbols are very small, make photocopies. (You're allowed to make copies for your own use, after all) You may need to drag out the big pattern to stitch where the pieces overlap, but for the most part you'll have a nice small stack of patterns to work with. If you have trouble with the size of the symbols, simply enlarge the pattern. Using a metal pattern board with a magnet to keep the place helps too. There are also magnetic magnifiers that magnify one line at a time, for people who's arms are getting too short