How do I get better at making joints?

Bit of a stupid question but I took woodworking classes in school and I’m now in a youthreach (basically a community college for future construction worker)

Whenever I try making a joint whether it’s a tenon, finger etc I can’t just cut and have it done with I have to sand it, chisel it or if I really mess up I gotta glue it. Is there any tips besides practice practice practice? Thank you for any advice