Your thread title asks: “How do you prevent being a spammer?” You might rephrase that to ask “what constitutes spam?”.
I think a reasonable way to define spam is: totally self-serving content that offers no real value to users. You might also add content and techniques that violate the terms and policies of the sites where you place your links (unwanted content).
None of the techniques you mentioned would be considered spam by the above definition, as long as you are posting useful and relevant content in a way that does not violate the terms of those sites.
Furthermore, you should not be concerned with the amount of promotion you are doing as long as you are using meritorious link building methods. You are not going to make anyone upset creating tons of useful content, save your competitors that you are leaving in your dust