I recently redid my tank with sand, using the following steps:
1. "Acquiring" eggcrate (the best I could find was bread delivery crates) and cutting it to shape, and washing it in the shower
2. Removing half of the old substrate using a new cleaning pan/shovel - this was so that I wouldn't screw the biological filter too much in one go
3. Washing the sand in a bucket - this was to remove fine particles which floated on the surface when given a stir
4. Turning off the filter
5. Placing the crating on the newly cleared tank floor (I have alot of sandstone, so its a must) and weighing it down
6. Placing the sand in the water - I used a bowl at a time instead of dumping it in, to minimise the cloudiness
7. Redecorating
8. Waiting till it was reasonably clear - i.e. I could see the back of the tank, kind of
9. Waiting a week, then repeating steps 2-8
I think it was a really good choice - not only has it renewed the look of my tank, it's also renewed my interest in it and launched the tank overhaul I've been thinking of for a year now.
Good luck
