I am blessed. We do not have an off season. We play the year round here in the southern part of South Carolina.

I use old tires and hula hoops as targets set a specific yardages on our practice area. I actually have two tires spray painted with our school colors. I split my boys into teams for competitions earning points by hitting their color tire or in etc...

Depending on where you practice the hoops might work best, if the club doesn't want you rolling out tires. Ha Ha

Step off your yardage instead of using a range finder. I find this old school method as a valuable step in developing the feel necessary to hit the shorter shots accurately.

I like to get down the range and practice hitting half, 3/4 and full shots with all my wedges. Once I start working out rough distances with each I work out what feels better I.e. do I prefer a full 60° wedge or a 3/4 56°........ and then when the new season starts I've forgot it all or it just goes Pete tong

I like to work on every ten yardage, 30 and 40 at a short game area and 50, 60, etc at the range. 100 and in is all feel for me. So I like to get a nice muscle memory of each yardage in the winter.

I bring my range finder to the range, and because the practice tee areas change forward or back every two days or so, I check the distances to various targets (yardage sign, patch of off colored grass, tree, etc.). I bring with me several wayward balls I have collected the week before on the courses I play. I hit these "extra balls" on the practice range to prove my established actual distances because we all know that range balls do not travel as far as regular out of the box balls. Usually about 10-20 yards difference. I take this into consideration when lasing the distances on the range. Yesterday? Roughly 200 balls with my 55* wedge (85 yards). The day before was 200 with my 60* (70 yards). Full flat swings to practice my slight draw with rollout and full upright swings for the downward strike for the slight fade hop and stop (or back it up). I finished out the practices with my 9, 6, and 1 (about 60 more balls total) but that was not the topic here!

The course near my home has an excellent short game practice area with multiple pins that you can target. Weather permitting, I'll spend 4 days a week right after work, hitting targets that are all within 75 yds. There are different turf conditions like tight and thick rough. Like others have said, I'll use a laser range finder to confirm distances. My goal is to groove a swing that can be repeatable and not require much thought when I'm on the course.

I spend time on my clubs chipping green from around the green to 75 yards trying all different shots ... low ..high etc
When I get to the course I let my swing take over and am confident then
Practice with a purpose

In this off season I was putting while watching TV.

Then I got a chipping mat and net. And started to chip practice balls across the kitchen.
My wife found out and now I am back to just putting every other day.

Now that courses are opening here in Iowa, I tend to practice at our course from about 40-70 yards in. After I tee off, and playing/practicing by myself I usually drop a few balls at different distances. I tend to address the ball with a little closed face so been working on trying to straighten that out so that I can get a straighter ball flight at the pin. Just got to remind myself to do that when nerves kick in at some of the competitive tourneys we do.

I use my flight monitor and hit various shots with my 50, 55, and 60 to determine length. IE 1/4 , 1/2, 3/4 , and full shots
Playing the ball in front, middle, and back to vary loft, and roll. This developed a great not only feel but improves ball striking.

Also depending what you are practicing use real balls similar to what you use on the course

No good hitting practice balls well then maybe getting yo the 1st hole and hit a similar shot only for it to get a totally different result more spin etc