As far as I can see link-exchange services do virtually nothing nowadays, at least it is clear that Google values them too low. Searching for new ways I discovered an easy method -- free Classifieds. So far they have no restrictions (neither code tricks to block the links). And the links you publish there are true normal ones. Except some classifieds that use closed databases where the links are not links at all, just an imitation. Fortunately, there are other classifieds that generate 1st class links (your backlinks), truly keeping your links on open pages. First of all conside these ones: www.backpage.com/
(partly free) and www.naturemethod.com/class/
(totally free). The first one allows to place several free ads (backlinks to your site), the second one has no limitations, you may place 100 backlinks in different sections if you wish, all for free and open to Google. Please note: if the classifieds does not use closed databases then Google robots consider each classifieds publication as a small article, i.e. each link is authentic. The only condition -- your ads (texts) should be different, no copy-paste. Even if you place 100 ads, all the links will be seen as unique ones. So, try it. Anyway, it is not bad to backlink you page among other classifieds. And besides, you also may offer your products and services there.