I've been recently how to avoid useless posts , and not to get Infractured or warned

So can you explain for me how can a useless post be , and give me an example
Also on spamming if possible

Basically, read this

The definition of useless post I keep in mind before posting is that it is a post which does not contribute towards the thread topic. This definition covers everything from off-topic posts to spam posts.

Always post keeping thread topic in mind and it's relevance to what you are going to post about.