Hey, i'm a beginner at SFM and i'm really having a hard time with joints getting all messed up and hair clipping, being an way experienced animator is there any tips for posing complicated positions and hair? Oh btw you are one of the best animators out there, keep the good work coming!
Not really, unfortunately. Just patience.
For the hair, if it's jiggly, then you can pose the controller bones (assuming whoever made the model added them). If there are no controller bones, or the hair is still being annoying even with them (like, for example, Lulu's braid), then you can always right-click the hair in the Animation Set Editor, and then go to Utilities -> Bake Procedural Bones. This will stop it from jiggling, but allow you to directly pose and animate it yourself.