Crash through walls trace the minifigure’s shape onto a piece of paper. Cut out the outline & place wall back onto set.
Use fishing line to make things appear to be floating
Take arms or legs off of a figure and use as spare parts or for closeups so you can manipulate them more easily.
When filming the firing of a gun, use a translucent orange cone (put on & off end of gun) to simulate a flash & sync with sound effects.
Use an iPad as a backdrop play a video/animation or have a graphic on screen.
Use flashlight to make things glow. Use the light on your phone too.
Create water by using clay or blue bricks and take some out and/or put back in between frames
Use clay that matches the base plates or figures to hold them in place.
Use one color of bricks as the chroma key color. Do not use them in the scene, but use them so you can key them out & create action shots.
Make sure your scene is well-lit. A flexible desk lamp is helpful.