Something I’ve seen people fail to do is watch the printer print. People go “Welp, I’ve bought my newfangled 3D printer, first out the gate I’m gonna pick out this giant model that I like, I’m gonna hit go, and I’m gonna go grocery shopping.” then they come back to a ruined model and a damaged machine and wonder what happened.
Start out small, and watch it print. You’ll find out what doesn’t work and how to design or slice around it.
And watch it print. Sit there and binge watch a season or two of Extrusion starring Nozzle and Build Plate. First of all, it’s got better written dialog and deeper characters than anything broadcast on television since my niece was born. Second, the folks who refuse to watch the printer print tend to be the ones wo go “It didn’t work. Why didn’t it work?” Watch it print, you’ll learn “Oh the part wasn’t being cooled enough so the edges curled, the nozzle caught on the curled up edge and the axis slipped.”
Do some of that, and you’ll start seeing the problems in the slicer before they happen.