Only LL surgery can increase your maximum (morning) height.
Poor posture can make you appear shorter and it's something you can fix.
Other than that it's over unless you're underage, but even then it's probably over. If you're still a kid eat, sleep, exercise and maybe try getting your hands on HGH.
I take glucosamine sulphate to maintain my morning height. I used to shrink almost 3.5cm (1.35") throughout the day. I'd wake up at 183cm and shrink down to 179.5cm after a long day on my feet. For those of you who don't know, everyone shrinks during the day because of gravity and spinal compression
Glucosamine sulphate has helped a lot, now I only shrink 2cm which is average for men. My spinal compression was quite extreme, though. It doesn't work as well for average people, but it "gave" me almost 1.5cm of height. If you only shrink 1-2cm, it'll give you 5mm at best.
I also wear small lifts (1-2cm) in all my shoes and have perfect posture. All in all, it's around an inch of extra height with no effort. The lifts I wear are so small I don't even feel them and glucosamine sulphate is only around 15 euros for a year supply.