Off the floor, stickered, away from light, no wide swings of temp or humidity. Do not store standing on end leaned against the wall. Periodically (2-3 times a year) unstack and restack with stickers in slightly different locations. Make sure all the stickers are exactly above one another to avoid the weight of the stack bending the stuff below.
That's what I do with my furniture wood.
Be aware that wood markets change. Stuff goes in and out of fashion and supplies vary. If you are talking buying stock blanks in things like curly maple, mesquite, claro and English walnut, it's a different game.
At one point several years ago, boat builders were in a panic 'cause Middle East buyers (at least they got the blame) were stockpiling teak against future supply problems. Hawaiian koa is in short supply because it's not being harvested except as salvage. News circulating among woodworkers is that there's a wee insect that's got into walnut trees in this country. I've heard of coming restrictions on shipping anything but kiln dried walnut. It's working its way east, and some foresters and dendrologists are predicting that American walnut will go the way of chestnut and elm. Gone, kapput, finished, no more. You might want to buy up walnut stock wood.
Your grandkids may thank you.
