Evernote & GTD
I have been using GTD for over 5 years (and it changed my life)!
I also use Evernote and stumbled upon "TSW," www.thesecretweapon.org, which is one method of using Evernote and GTD. It is fairly easy to configure, and I bcc emails using the setup they recommend. I have two jobs (one where I travel; am an adjunct professor for an online university) and am fairly ADHD, so it if works for me....
I actually found out about TSW here on the forum, so you might do a search on the forums after you check it out, if it interests you.
TSW is free and they have a pdf "manifesto" that you can download.
Of course, as most will tell you, there are a myriad of implementation methods, so you always have to find out what works best for you. As you are already using Evernote and familiar, TSW might be an easy-ish transition for you.