Generally you want to keep the BEER inside the fermenter within it's optimum temp range, and without much variation, during the first part of fermentation when the bulk of conversion is happening.
After that you want to gently raise the temp some to keep the yeast going and to promote cleaning up. This doesn't have to take very long, though. Once you're at terminal FG, just raise the temp to something like room temp (high 60's, low 70's) and let it sit for a few days, maybe 3. At this point you can dry-hop, too.
Before you bottle or keg, though, I'd cold-crash it by putting it in a ~40* environment (something above freezing, but cold) for at least a few days to drop everything out and clear it up.