I've been asked this a couple of times before, so here's the way I do it. Do bear in mind, every model I assemble and paint is for the purpose of gaming. I'll never put in the effort to paint a model unless I'm going to put it on a gaming table and pop a can of whupass with it. As such, I will probably never reach the lofty standards of those magnificent pro painters at Cool Mini Or Not. Anyway, enough talk. Here's how I base my minis.
Step 1: Minis on their bases. Here we have plug n' play marines sat in their bases. I suppose if they weren't rank and file, I'd give them a little more love and file down the tab until it's level with the base, but naaaah...
Step 2: Glue! I use this stuff.
Yeah, as you can see I've been using this bottle a LONG time. 3 years, I think. Use an old brush and apply a layer of the stuff, like so:
If, like me, you live with pets, you might want to keep an eye out for unwanted fur. Make sure the whole base is covered. Work quickly with larger bases.
Step 3: Drown the bugger in sand. Your favoured texture may vary, but just make sure you have a nice big tray to completely submerge the model in.
Don't be shy with the sand...
Step 4: Turn the model on its side in the tray and tap away the excess, rotating as you go. Unfortunately, I needed both hands for that so no picture. Here's the end result:
At this point, feel free to use your fingers to wipe away any sand hanging over the edge.
And that's how I sand my bases. It's worth pointing out that it helps to plan ahead and think about where you can reach with your brush before gluing the mini on its base, especially with more complex minis like the IG Heavy Weapon Teams.
Thus concludes part one. Stay tuned, in the next part, I cover how to paint these bases.