I thread my needle before cutting the thread so I make sure I'm loading it the right way. Also, I find beeswax helps & as others have mentioned, keep it about the length of your hand to your elbow. Finally, I keep an eye on my thread as I'm working. Sometimes when I'm working on a very curvy piece, I will unintentionally twist my needle as I'm shifting the fabric to get a better grip. If I notice that happening, I grab the thread going into the fabric & gently untwist the other end (sometimes just letting it hand down will prod it to untwist itself). That usually only happens when I've chosen a longer piece of thread for some reason.