Tips for longer-term storage?

I'm a pretty casual smoker ~2-3 times a month, and when I'm back from school I usually am not able to smoke that much due to parents and other concerns, so when I buy, its usually only a gram or two. By the end of the time I'm home and have to leave for school again, I always end up have a little bit leftover, and not being one to waste, I usually continue storing it in a baggy, in a pill container, in another plastic bag hidden away. However, storing like this does not do wonders for preserving quality. Are there any ents out there with better long-term storage ideas? Has anyone tried vacuum sealing? Has anyone tried freezing it like you might freeze and store a steak?