Yeah, avoiding hyper tier stuff takes some work, but you learn to sort things out with enough time.
You can generally divide muscle girls into around three categories, light, medium, and heavy, and I just so happen to have a presentation on this very topic
So, starting with your generic looking sexy lady as a base, the type you see in just about anime or as any pretty girl model out there. Light starts off by simply adding some tone, usually around the stomach and that's it. This is the type you'll most often see when some writer wants to say a girl looks muscular but doesn't want to actually commit to making her super buff, just give her some light abs and that's it. Occasionally you'll see some tone on the arms as well but that's pushing it
For the male equivalent see the main character of just about any harem or echhi anime out there, they got a tiny bit of tone but not enough to detract from them looking 'cute'
For artists, try looking up dandon fuga, he does alot of good work of this kind.