Key words for playing fiddle or violin? "Listen, Listen, Listen!"
If you pay close attention to the sounds coming out of your fiddle, whether bow or intonation, and adjust accordingly, you will be that much closer to playing well. There is a "right" way (or series of right ways) to play, and you should be able to hear when you have it. If crunches, play lighter. If squeaks, try applying more pressure, and make sure the bow is being drawn at least close to perpendicular to the strings, all the way to the tip, and roughly over the f-holes. Left hand fingers should be firmly planted, with just enough tension to hold them onto the fingerboard. Upper bow arm roughly parallel with bow, no matter the string. Of course there are exceptions, but if you LISTEN you'll figure it out.
Pioden