"So how to get backlinks than ?" - this bugged me, what have you been doing upto now to get links, if you have been performing black hat techniques (http://www.pushon.co.uk/articles/top-5-white-hat-and-black-hat-search-optimisation-techniques/) then it might be worth giving up on your domain, and starting with a new domain (especially if you have a penalty) or trying to remove the penalty before you start doing any of the below.
there are many ways to get good quality links without guess blogging. Ive never done guest blogging and wouldn't do it on low quality sites, writing a great article on youmoz is different and can get you some links, but that is a different debate (see here http://moz.com/community/q/could-posting-on-youmoz-get-your-penalized-for-guest-blogging
I could spend days writing a huge articles about ways of getting links without guest blogging, but I will keep it relatively short.
1. How about writing and producing great content on your website that people want to link to.
2. If you sell products, send them out to some influential people in your niche and ask them to review (not guaranteed to get a link, but usually works)
3. Out reach, contact people in your niche and offer advice to help their articles and see if they can quote you.
Below is some great articles on helping you, I would also recommend watching Rands WhiteBoard Friday and subscribing to Matt Cutts on Youtube
http://moz.com/blog/google-traffic-links
http://moz.com/blog/earn-higher-rankings-without-content-creation-whiteboard-friday
http://moz.com/blog/filthy-linking-rich-how-to-passively-attract-valuable-links