Can i do Da'wah?

I know I'm not a good muslim, I do not pray as much or as well as I should, my ikhlaq (character) has a long way to go to reach the level required for a mo'min, i do not have enough knowledge (what is that, anyway), i sin often and do not ask forgiveness often enough... i know i'm not a good muslim. How can i do da'wah? thats for the good people to do.
I have heard many revert stories (they are so interesting and an eman rush too), mostly i noticed how they were led to Islam through their own intellect and the search for truth or were influenced by some "good" muslims. Recently though, i have been exposed to a whole new kind - reverts who were led to Islam by totally non-practicing muslims. Now is that something those muslims should be proud of, not necessarily because when Allah decides to guide someone, He will. SubhanAllah! But it got me thinking, those muslims probably dont even know they influenced someone so much. I probably dont know how i influence people either. I can only wish, someone - even one person has been led to the right path through me. But i dont know, and im not doing it consciously so i will never know.
Coming back to the first question. How can i do da'wah? I can, because its in my fitrah to leave an impression upon people - through the light of Islam thats in my heart. I just need to be aware that i am in that position, where people around me could be seeking peace or truth and find it through an action or word of mine.
I dont know if this write up is cohesive. But i just pieced together the ayah where Allah says He has raised up this Ummah "for" the people (which necessitates enjoining in good and forbidding evil.) with these revert stories because even in our ignorant stupor, we are innately leading people to the truth. However, to reap real results and actual reward, we need to be aware of this influence.

كُنتُمۡ خَيۡرَ أُمَّةٍ أُخۡرِجَتۡ لِلنَّاسِ تَأۡمُرُونَ بِٱلۡمَعۡرُوفِ وَتَنۡهَوۡنَ عَنِ ٱلۡمُنڪَرِ
Surah Aal Imran Verse 110 

Pls do comment and let me know if this made sense, or you got what i was trying to explain. JazakAllahu Khairan