First of all...only do-follow links are not necessarily require to achieve better search engine rankings. For achieving do-follow links; you should run some link baiting campaign depending upon your target market. i.e: if you own weight loss related website,you can provide BMI calculators badge that can be embed in blog and put link back to your website in "Powered by xyz"
There a lot of dollow links on the internet. You can seek them at Google. Such as article directories, press release, forums, blogs, and more.
Don't go for do-follow links only. Try everything and create this perception to the search engine that you are natural.
It doesnt hurt to have some no follow links but you will want majority of them to be do follow around 80% do follow and you will be fine. As no follow you still can receive traffic from and look natural.
It´s important to diversify your link building. So do not focus only on do follow sites! It´s also a fact that Google notices and values "no follow" links to determine your rankings! So will be a no follow link from Wikipedia always more valuable than a spammy blog comment or forum post, but never as powerful as a do follow link from Wikipedia, as example! Hope this helps
If you’ve been doing any kind of reading about link building, then you’ve probably seen people mentioning “nofollow†and “dofollow†links. These are very important terms to understand when you are trying to build great links back to your site in order to increase your search engine rankings.