Aselam aleykum
I think the first step is that you have to accept that no matter how hard you try, you'll never be perfect. But that's ok. Allah subhana wa 'atala doesn't expect you to be something which is impossible.
If you don't accept your own imperfection, Shaytan will try and use this against you. Of course accepting your imperfection doesn't mean you can lay back and take it easy. What's important is that you try to do your best, but that you realize that you won't be held responsible for what is beyond your capabilities.
The second step, is to get some perspective on things, here's a radical concept of which I'm sure many members here will disagree:
- We're here on earth to be tested (so far all muslims will agree). But the test is not how well we can implement the rules in our life.
Haram and Halal, fard ans sunnah, they are not the test. Instead they are part of the guidelines that will help us with the test.
The real test is, wheter we're a good or bad person, how we deal with others, and so on.
So stop stressing out on wheter or not you used the perfect words in your dua, and focus on ichlaas instead. Or when your are distracted during prayer, just use the prostration of forgetfullness and accept that Allah subhana wa ta'ala has made things easy for us, so don't make it hard.
PS: I also second what ardianto said, be carefull with teachers, and kissing the name of Allah is not of the sunnah