Okay Guys... Now, check it..
1) Sale and Purchase Links.
Ok, this one is difficult. Perhaps my friend already knew this, google is so hated this. do not think my friend can do a cunning way to cheat google. Remember, we google this one really hates blogs that toying with her self-esteem .

2) Affiliate links Uncloaked.
Why Google hates affiliate? Google seems to hate everything that smelled like a commercial, if it makes money for my friend, Google does not like it. Unless of course you pay for Google :D, as in buying Adwords for PPC. Then they'll love you. hahahaha.

3) Create a link to the blog spam
Notice relax on who comment on your blog DoFollow. If the link to the site they slouch in the eyes of google, please delete their comments.

4) Blogs are not active.
When the google robots visiting your blog and your blog is in a down server. It is certain that the blog has long been perched on the SERP going to slip away.

5) Duplicate Content.
OK, I guess it all easy to know. If you do copy and paste carpenters blogs of others, from now stop it because it will destroy the image, your self esteem in the presence of other bloggers as well as before google. repentance so quickly ... :)

That's five things I know, not a good idea to be implemented :)