There are loads of such "tips and tricks". Buy or borrow books and read them carefully, reread them from time to time. Use two very large mirrors to control your posture and movements; compare them to what you see of good violinists on YouTube. And, of course, listen to yourself very critically indeed. Make recordings.

If you can afford it at all, consult good teachers from time to time. Do not ignore their advice; if in doubt, consult other teachers.

Is there a difference in technique between Folk and Classical fiddling? Yes, there is, but it is not as marked as some fiddlers pretend. Most really outstanding folk instrumentalists have a "classical" training.