The good thing about organics is that if you are starting new to organic lawn care, the first step is to do nothing. Stop putting chemicals on the lawn and let your lawn detox. It may look worse in the short term, but long term you
should be able to get it looking as good as anyone else's lawn.
I'm in Oklahoma too and unfortunately I think it's too late for the Corn Gluten Meal to prevent weeds since a lot of the weeds have already germinated.
The best place to start is to
water deeply (1" once a week) and mow high (don't bag the clippings).
You can put down some organic fertilizer that should help to green up the grass. I hear a lot of people mention Ringer Lawn Restore. If you are near a Do It Best hardware store that will allow you to use the ship to store option, the shipping is free. Here is the link:
http://doitbest.com/Lawn+fertilizer+and+rose+and+garden+fertilizer-Woodstream-model-9325-doitbest-sku-734217.dib. Otherwise you can google Ringer Lawn Restore and there are lots of websites that
sell it and ship it to you.
Good luck!