Now that's a very open question
So much depends on what they look like and what you expect.
I always work on the roots regularly. Good nebari can lift a mediocre tree to a better bonsai so I'd say work on the roots at the first opportunity.
As for trimming the branches: Free growth will usually give maximum trunk thickening but that's not always the best way to bonsai. Thick trunks that have to be chopped can take many years to heal the large cuts and may always look like a stump instead of an elegant tree. Regular pruning gives me far better options for when I eventually prune down to bonsai size and several smaller cuts heal much quicker than a single giant one.
For more specific advice you should post some pictures. 1Mb file size limit for ausbonsai attachments so you may need to reduce file sizes to load them.