Hi. Welcome to the site. I have had my little girl for only 6mnths and she's my first also so I'm no expert but after months of trial and error I finely have her glass vivarium regulated. The best advice I got was to insulate 3 sides and the top. Lot's of different ways to do that but what I used was black foam board, high heat duct tape, and decorative cling for esthetics. Here's how it's done.

1. Measure and cut the foam board to fit the 2 sides, back, and top of the tank. Cut a hole in the top piece for your light and a couple of smaller holes for air.

2. Cover 1 side of all these pieces with the duct tape.

3. Place the decorative cling on the glass and the foam board behind it, duct taped side against the cling and facing down on top.

4. I used black duct tape to secure it all in place.

Once it's insulated use a UTH pad with a thermostat for regulating heat. Use a temp/hum meter with a probe for measuring levels and I place a small bowl of water on the warm side of the tank to raise the humidity. Plus I use coco substrate because it holds moisture longer.

It's a lot of initial work but it's much easier to maintain temp/hum levels and it looks great. Here's a picture of mine.