If you get stuck, look for 2 or 3 letter words such as do, so, and, the, etc. Ruzzle is unique where it will accept 2 letter words. You won’t get a lot of points for these.
Find plurals of words. If you can make TREE, see if there is an S! This works for all kinds of suffixes– D’s, R’s, ING’s, etc.
Look for words that rhyme. If you can make DARE, check to see if you can make CARE, or BARE, RARE– as long as you can reach the next letter from your starting title, you’re good.