If it is new websites. Check the pages in your websites are indexed in your search engine. If it is indexed in search engine then start doing back link for your new websites
To be on the safer side start of with placing signature links in Forums, the one main factor is don't vary too much on your backlinking speed. Limit it to min at the start and then scale up your speed of backlinking.
Article submission, social bookmarking, blog commenting, forum posting and link exchange is the popular ways to get back-links.You can stare getting one back-link everyday. this way Google will not penalize you.