as per photographing your minis,... simply using the "macro" function can do wonders for the focus. And maybe set your iso speed down around 100 or so to start. You can adjust later if necessary
Other then that, a single piece of paper that the model sits on, and "rounds up into the backdrop", will help eliminate that "background edge" in the image.
And you don't need a tent, so much as at least 2 lights. One from about 45 degrees left, and one from about 45 degrees right,.. and a bit overhead. These help to cancel each others "shadows" out. A third light can be done usually from center-overhead-ish,.. (and this light usually has a diffuser of some type to soften the light even more, but that's a bit more advanced)
Not that I'm a photo genius or anything. But I've been through this process, and thought the info might help.