Best thing to do would probably be to begin reading some of the chemistry articles in the RC forums. Here are all the chemistry stickies which have a TON of info in them.
http://archive.reefcentral.com/forums/showthread.php?s=&threadid=102605
I know it will make your head spin if you get into to much scientific stuff at once so pick a topic like "Nitrate" and read about it for a couple days. Do it in small batches so you don't hurt your head

There are Nitrate reducing items sold by many companies, most of the people I know use a deep sand bed for denitrification. you can also look into one of those nifty sulfur denitrators but it's another item you would have to buy, adjust and keep an eye on. If you like gadgets then the sulfur one is the way to go. If not, try some of the natural methods. If you don't want a deep sand bed in your display tank you could look into the "remote DSB in a bucket" method.
According to the chemist Randy Holmes-Farley you should aim for an Alkalinity in the range of 2.5 - 4 meq/L or 7 - 11 dKH. Most of the hobbyists measure in dKH instead of the way you listed yours (meq/L)
Also, don't try to correct all of the issues at once or do any of them too quickly. Most corals can handle a broad range of Alkalinity but if you change your ALK by 2 points in one day you will have trouble with almost any coral and most likely lose a lot of them. Do your changes slowly over days or weeks.
Your pH is looking good at 8.4. Most people aim for 8.0 - 8.4. It will fluctuate a lot and depending on the time of testing it could be off by quite a bit. I know people who can't keep their pH above 7.9 but the corals are fine. Again it is a matter of keeping things steady and letting the corals adjust.
It sounds like you are getting a good base of knowledge and just have to build on it slowly. Keep reading and enjoy the hobby. A lot of people spend so much time testing, adding chemicals, testing etc... that they don't ever get to step back and just enjoy it. You will never get everything perfect and just when you do something will change and you will try to fix the next thing.
Good Luck!
-- Kevin