I went about starting my cellar relatively late in my pipe smoking adventure. I had tried various blends, but in a haphazard way, without documenting them with my notes on those I like and the ones I didn't.
I went to SP and had a look at their best selling bulk and tin blends and ordered 10 from each category based on what I remembered I like about certain tobaccos I had tried before. From there I started taking notes diligently and found that I was veering towards a particular tobacco, namely, Orientals, Virginias and Scottish/Balkan mixtures.
With the rumors about Dunhill, I bought up 10+ tins of the blends I liked by them, particularly Aperitif, EMP, Royal Yacht and Dark Flake. From there, I continue to use the method of buying 2 at a time for new blends I came across, one for now and one for later, as described above by others. For bulk stuff, I kept my orders small, until I found one I liked. Then, I got a pound of whatever that blend was and promptly stored it in mason jars.
Since there are a multitude of blends to be sampled out there, I am continually finding new ones that I like. What is important to keep in mind are the FDA regulations that are looming. If the blend you are looking to cellar is on the chopping block, then you would obviously want to buy as much as you can. One easy way I've found of verifying this is to look on tobaccoreviews.com for a review prior to 2007. If there are no reviews that far back, start buying that blend now before it's gone.
Here in NYC, space is at a premium, so I do not have the luxury of a smoking room/office or even a front/back porch or garage. I have a modest pipe cabinet where I keep my pipes and jars/tins, with some other hidden spaces throughout the apartment to house the overflow. As long as it's dark and the temp is consistent throughout the year, you should be fine with storing.
Good luck. If there's one hard fact I've learned this year with my cellar, it's that TAD is just as addictive as PAD!