Presuming the micro-adjustment is at full length at the clasp (i.e. the last link is set to the very last set of holes), your only real choice is to add links.
In order to do that, you'd need to know what kind of bracelet you have; is it gen (i.e. 19mm 7835/78350 etc)? If so, is it with rivet links, folded links or screw pin links? Is it rep? If so... You would be well advised to know what the lug width is (there are some reps out there with 20mm instead of the correct 19mm) as that will effect the size of the clasp end links. Does your bracelet have solid mid-links, or are they hollow?
Getting the right size links sounds pretty straight forward, and for a genuine watch/bracelet it is; there's only a few options in that regard. But if you have a replica or aftermarket bracelet, that introduces a whole lot of other potentials and factors that need to be accounted for in order to find the right links to lenghten the band, as some links may not be suitable or compatible for certain bracelets.