Search:

for increasing page rank. you need to get high page dofollow backlinks. as faster you get dofollow you will get page rank 1 When Google update his page rank.

for SEO step by step . you should read Google basic guide or SEOMOZ basic SEO guide .

400 to 500 words best length for article. You can target three keywords on one article. If you posting article on article websites so no need to do over bolding.

They all are best SEO technique , if we do without spamming so we can get good result.

Profile links still work ? as we know Google don't give preference to profile backlinks.

They are not all Dofollow. checking more then update here.