Cover and concealment are the that can help you take and maintain a position of strength in a gun fight. IDPA and pretty much any other practical shooting organization make this part of a high percentage of their CoFs (course of fire).
Using concealment is grounded in tactical logic: when engaging a threat present the smallest target (read: your body is the target in this case) you possibly can. IDPA rules require at least 50% of your body must remain behind cover. Other than in a match how can you practice this?
I found a way to do so that requires a few common items: cardboard, some good bourbon and a table saw. The box below used to contain a bottle of st Kentucky bourbon.
1. Start with a box like the one above- the bourbon is a bonus for use elsewhere.
2 . Note the edge of the box inside the red rectangle above. That edge needs to be cut off the box to leave the other grooves for the sliding box lid intact. I used a table saw to get a nice clean cut.
3. Now you should have a box that looks like the photo above- with grooves that now can support a piece of cardboard with a nice 90 degree angle.
4. Cut a piece of cardboard to a size that fits the box and is tall enough to use for concealment if you set it on the shelf in a range booth.
There you have it- set this up in your range lane and you can practice leaning out to shoot and leaning back in between splits.