So, you've got a great song coming along. You've got the refrain and the basic chords down. Then you get writer's block. What are your suggestions for getting out of it?

Time...sometimes waiting is all that's needed. Don't stress too hard, the idea might need a suggestion from someone else, or a trick you haven't learned yet. Maybe some experimenting - change the key, do a question/answer between a couple of the parts, add a grand pause...

Sometimes working on another song will help. It either clears the cobwebs out or it might spark a creative thought on the original project.

I've had ideas lay fallow in me for a long time (decades) and then bubble to the surface, and sometimes I've had complete instrumentals that after a similar period of time I play the song and go "Oh wow! Lyrics!"

Yeah I find that happens when I'm forcing it too much.