In my case I did not completely adopt GTD. Instead I improved my own approach with ideas from GTD. The biggest change for me was the usage of a so called "hipster PDA".

As you can see it is nothing more than a bunch of index cards which are being hold together by a paperclip. On these cards I note immediately if something pops up in my head which demands an action. By doing so I effectively remove a lot of stress which comes from worrying that I might forget to do something. At the end of every day I look which stuff I actually want to do and sort it into my actual todo-system. My favourite thing about the "hipster PDA" is that I always throw away the old cards. Therefore old tasks cannot distract me anymore. That's one thing I never liked about traditional notebooks.
Another GTD rule, I strictly follow, is that you should do everything which takes less than two minutes straight away. By doing so I effectively remove all the small tasks which normally clutter my todolists.
For organizing all my todos I use stikkit which offers more functionality than tadalist. Especially the tagging support and the possibility to schedule tasks in a calendar + email reminders are two features which I do not want to miss.
Adopting GTD is not done overnight since you have to tweak it in a way that it supports your own style of working. However I adopted a lot of the core ideas and could see how they improved my productivity and reduced my stress level.
For more information regarding GTD look at the most known website on GTD 43folders or check out the book from David Allen.