Very simple tricks are almost always the most useful. While painting my mini's before I base them I generally place the pins in the feet and then use corks from wine bottles to hold them in. I just find it easier to paint them with the ability to remove them from their 'holder' before I base them. Another benefit to doing it this way is when using an airbrush or priming.
I always use a flat piece of cardboard to spray against when painting, the last thing painted on this one was drop pods as you can still see the outline. I set my wine cork on the cardboard and run a paper clip through like so:
Bring out the end and curl it around on the bottom of the cardboard to hold it in place like so:
Now use the pins on your models feet to hold him in place on the cork:
You can even stand it up sideways:
Like I said, very easy to use trick that is pretty useful for the way I paint but might not be helpful for everyone. But it might give you an idea or two about how to change things you already do to make it easier for you.