What all are the things that can prevent you from getting high SERP ? Duplicate Content Link Spamming OffPage SEO not done Any more ?
Link spamming? What kind of link spam do you mean? If you mean backlink spam then doesnt that mean technically If I didnt like your site I cud just spam backlinks for your URL and google will punish you... Cant be?
There are many factors that could hurt your serps like building links to fast or not steady enough. Bad on site optimization can hurt your rankings. Getting links from bad link neighborhoods or excessive link exchanges. Too many non relevant links with wrong anchor text could also hurt ya. Hmm instead of trying to list everything myself read what Google has to say about it! google.com/support/webmasters/bin/answer.py?hl=en&answer=35291
to put text using font size 0 to put content with text color same as background color to put text behind images to put big flash file which take more time to load to put cloaking the list is big but these are the main point which may hurt your SERP
There are a whole bundle of things that could get you banned but I guess one of the main ones is primarily linking to bad neighbourhoods yourself. Google doesn't really mind where your inbound links are coming from. If they are non relevant then they will just ignore them but they do pay attention to whom you link to