M'ath, zhey Veryofi! Welcome to the learn Dothraki and Valyrian forums. Sorry, its a little quiet here these days. At the moment, I am being overwhelmed by stuff going on in my personal life, and have not been able to spend much time here.
There are a couple other users who check the forum from time to time, notably Qvaak. He is exceptionally good with the language. I'll answer questions as well, but not as accurately as he can. Like you, my grammar can be a little rough.
But one thing you will find here is the most up-to-date information on the language. Even though it has not been updated recently, the wiki and dictionary are pretty much accurate. There are a few words from David's book that haven't been added yet, as well as a few minor corrections. But nothing earthshaking. And I am hoping for a little free time later this spring to finally get these added (I have been working practically every weekend since the book was published.). There will likely be some new vocabulary as season five of GoT gets underway. Make sure you check out David Peterson's blog at Dithraki.com
The grammar sections should be correct, as far as we know.
How did you go about learning Dothraki?