As many have said before...make sure they are cracker dry, then vacuum seal them properly and they will last for many years. Just store them in a dark place that maintains a consistent temp, generally speaking. I do not know what keeps more people from using a vacuum sealer (same with sheets of blotter...will last practically forever).
Even better in my opinion is to dry them then grind them to powder, then of course vacuum seal them. That way, you just load them in 00 gel caps which hold about 3/4 of a gram per capsule. For anyone that never took 4 or 5 grams this way...try it. You start to feel it in a few minutes, and at 30 minutes you're getting donkey-punched. Hard. And if you prefer a toss and wash type thing, mix what you want in a glass of OJ and it will happen even faster.
If you want to use them fresh, you can pick them, weigh them ( remembering that they are 90% water, so obviously adjust accordingly), throw them in a blender with OJ and prepare for launch. It can be hard to choke down but the OJ does help a good deal. It is as close to instant onset as you can get, but be prepared. You will feel it with less than ten minutes and again, by the time the 30 min mark arrives you will be utterly smacked. Guaranteed.
(Just as a warning...if you tend to get nauseous easily, the wet variation with the OJ may make you want to boot, especially with larger doses, which I consider to be 3-6 grams or so, which would be 30 to 60 grams wet, roughly, remembering they are 90% water. That is quite a bit to take in the blender method, but if you are going all in? It hits hard and fast and it really is something.)