[HELP]I have some questions about IM.

Hello guys.
i have been reading about IM since about 2014 but never got to implement the knowledge. I am now thinking of getting seriously into IM but I need your help with some questions.

If you're just going to roast/troll me, please don't. I might kill myself. So anyways, the questions are

1. Is clickbank still profitable? If yes, what should I use, amazon or clickbank for an affiliate site?
2. If I reside outside US, can I use amazon.com affiliate?
3. If the front page on google search for a niche topic/category is occupied by amazon or any other big brands(nike, levi etc) is it still rankable for a newbie?
4. If the front page on google search for a niche topic/category is occupied by niche sites, should i skip this niche?
   
5. In a niche in health e.g. blood sugar, if the front page is full of authority sites like webmd etc. should i frigging skip here too?
6. What are the common mistakes while choosing a niche?
7. Any tips on how to choose a niche?

Thanks.
(please move to appropriate category if not already)