My favorite basing technique over the last year or so has been to sculpt a surface directly onto a base prior to attaching the model. This is similar to other basing techniques that I have written about, but rather than gluing a tall bit of material onto the base, I add details to a thin layer of greenstuff or other 2-part putty. This technique is a bit (only a bit) more time consuming than gluing on layers of rock, cork, or super-sculpy, but allows for much greater control in the design of the base. This is also a great way to get a handle on the properties of greenstuff if you are just starting out as a sculptor.
One of the excellent things about putting the time in to really craft your miniature’s bases is that it gives you another way to tell their story to the viewers. The Eldar that I have been working on are scouring a rusted wasteland of a planet in a region littered by centuries of wreckage and scrap. Having a distinct idea about the environment that your minis are in can add a lot to the miniature itself.
I like making bases this way, especially if I am working on some other sculpting. This gives me a way to use spare putty that would otherwise set up and go to waste. Its also relaxing to work on these as the level of detail needed for them is not very fine. Of course you could simply purchase some resin bases from one of the many manufactures out there. If you want your own design or style, this is a great way to go about it. Feel free to ask any questions in the comment section!