Welding Tips and Tricks

I'm trying to get better at welding and am hoping one of you experts can provide me with some feedback.

Some context... for this project I'm making a square out of 4 peices of 1/8" angle iron. Here's a picture of the joint I'm trying to weld: I'm using 6011 electrodes at 50 amps on an Everlast 200st inverter. Initially, I tried welding downhill on the corner joint but ended up burning through the angle iron. Do I need to lower the amps? How do I avoid burning through at the bottom (end of the weld)? I then realized I could weld the thing in a flat position. The weld ended up looking better but still not great. Any feedback would be greatly appreciated!

Corners or edges that could potentially cave in I always weld in a large tack before anything else. That way if the heat outrun the weld bead, there is additional mass there to act as a buffer and won't give in as quickly.

Oh and always practice on a simulated joint before heading on to the actual project.