Independent thinking has to be practised over time. It cannot be learnt from a book. Just like you cant learn swimming by reading a book. You need to actually get into the water and do it.
Books, and videos etc, help in creating a meta-framework - how to think about thinking. Any good behavioral psychology book would be helpful in this regard. The absolute BEST place to start is to read Charlie Munger’s Psychology of Human Misjudgement.
More importantly, now that you have realised your bias(es), just go ahead and do what you think is right. No amount of intellectualising will help. It seems you have, what is known as “authority bias”, which is you are getting influenced by people who you think are experts or authority figures.
The best way I have tackled my biases is to maintain a checklist for myself. If I am putting in serious capital in any stock, I go through that checklist. You could try it. Simple points like reading the entire VP thread on the company, waiting for 1 week from getting the idea to actually buying it, reading at least the last 3 yrs annual reports or last 3 concall transcripts etc can help you build conviction.
Also, force yourself to write a note on
i) what the company is about
ii) why you are investing in it and
iii) why you think it will do well.
The note need not be very long or elaborate. Even 2-3 lines answering each of the three questions is fine. But you must do it. The reason writing a note is important is you will probably feel really stupid writing down “X has bought it or suggested buying it” under reason for buying!!