Small Stakes No-Limit Hold'em

I'm by no means an expert, but I'll give my 2 cents…

I was always a little unsure of what "weak-tight" means exactly anyway. I assumed it either referred to a loose passive player (calling station) or perhaps a super tight knit. Regardless, from your description, if I had to label you, I would probably classify you as more of a knitty TAG type.

You seem fine preflop, especially for microstakes, as you are mostly raising with your good hands, and 3 betting in good spots. As you said, the issue is coming up postflop. You seem to shutting down on the turn a little too often, and maybe shutting down a little too quickly when you face resisitance. With your strong hands, don't be so quick to fold. When you do this, you are giving your opponent's very good fold equity against you. A astute villain may think he can simply bet you off of most hands when you don't show strength.

Now you are correct in not bluffing too much in the micro/nano stakes. Value betting will still be your big money maker. However, you will still run into some very bad players at those stakes who may be bluffing you off too many good hands. Try being a little more aggressive on the turn and the river when you have a good hand and/or position. (maybe throw in a few more checkraises early in the hand, so your opponent will be forced to define their hand ASAP)

More postflop aggression may also help you get paid off on your big hands a little more often. If you start showing more aggression postflop, and even bluffing a little in good spots (heads up/ in position/ against non-calling stations) they will be less likely to shut down when you have a monster hand. You have to give a little action to get a little action as they say.   The problem for you currently may be that if a decent regular has HUD stats on you, he may notice that you only show aggression postflop with very strong hands, and he'll just shut down when you not passive postflop.

Microstakes success is generally about value betting good hands, but since more and more players know this too, you can adjust and also win a lot of dead money in smaller pots with well timed bluffs/semibluffs against the knits, setminers, shortstackers, and tighter TAGs. (the key phrase here is "smaller pots") The "big pots for big hands" rule is should still be carved into your eyelids.  

So in a nutshell, balance your postflop betting lines a little better, by occasionally playing some big hands passively to trap, and also throwing in a few well timed bluffs against tighter opponents (there are plenty at the micros), and you should be good.

By the way 3bb/100 is not bad at all, so just tweak your game slightly. No need to do a complete overhaul.