The newest tent care tip I picked up this year is to never fold your tent the same twice. Many new tents recommend you just jam the tent into the bag without folding or rolling at all.

The instructions for my Nemo are just that way. Jam it into the included waterproof sack foot first, close the waterproof roll top and you're done.

Over time folds weaken the nylon and promote leaks and/or tearing along the fold. Same goes for tarps though depending on how stiff the material is that could be easier said than done.