Porter fermentation - perfecting

Hey I'm looking for some input on my porter.
I made a partial mash beer and it has been fermenting for almost 3 weeks (on Tuesday). I have been brewing a few years and feel like I've always ended up hurrying my beers through this period, bottling after 2/3 weeks, once fermentation has finished.

My beers have also been consistently "ready" after 10 days (3 days of constant desired FG). This beer, as usual, reached 1.012 after 10 days and has stabilized, and currently tastes really good too.

On the other hand my beers have often ended up tasting not quite as good as I'd like (subtle flavors that I don't want/like, low clarity, hazy, over-foamy, under-foamy, poor head retention etc).

I have time now and want to make sure this is good, I want to eke out the imperfections in my brewing style.

What shall I do next?

Leave in primary longer (how long)?
Move to secondary (how long/why)?
Bottle and age (how long)?

Just looking for some general input and expertise here - any comments are welcomed.

Cheers!

In my experience, after 3 weeks, you're beer is ready to bottle. Unless you did any secondary additions. I find that my porters are good after 3 weeks in the bottle, but better after 6-8 weeks in the bottle.

More important than time requirements, make sure you're yeast are as happy and plentiful as you can. Once I took more care to pitch the proper amounts of healthy yeast and ferment at the right temperatures my brew quality really went up. Maybe you're doing this already, but I thought I'd throw it out there.