As I see it, there is no trick or any methodical way that can make you think in a foreign language. It is directly tied to how much time you spend with the language, or to be precise, how much impressions of the language your brain has experienced. So, to be able to think in English, you must put in the necessary amount of time and effort. And I believe what's important is the exposure itself to the language in whatever way. The method itself is secondary. For example, let's say you attentively read an English book for one hour everyday. If you continue it for more than a year, I bet you'll start to think in English a little. I think common sense tells us there is no other way. If there is a magic way that works, it would have been discovered by now given so many learners who went before us. Even with all the advancement in information technology, all we see are wild, unproven claims. That proves there is no special fast way.

Well don't get stressed about it, it's natural to get blocked, what is more important is how you deal with it. So basically when you feel blocked, which typically happens because you want to say something specific, try to rephrase it or simplify it until you can say something like what you want. Then continue. This is useful practice as you will always encounter things you can't say in a language so developing the ability to find another way to say it is really useful. Reading novels in the language you are learning is a great way to develop a feel for the language.

This article has nice tips, I recommend the reading: http://www.lingholic.com/thinking-in-a-foreign-language-how-to-do-it-and-why/

have you interacted with native speaker? just thinking in English without your native own language.

I love it