Backlinks are an important traffic driver, not just for the search engines algorithms but to ensure that your site is listed in as many places as possible to capture extra visitors.
The important rule of thumb is Complementary not Competitive. So, if you are promoting training seminars for the doctors and therapists, you need to be on sites which don’t also offer the same services, but offer advice, support and help to doctors and therapists for whom your training seminars and events would be of interest.
Establishing backlinks is a long, hard slog and you should aim to set a target for finding and establishing backlinks each month so that you are slowly, but surely increasing the number of places where a link to your site is featured.
Some SEO companies look to achieve around 5000 per month but for many this would prove almost impossible without a dedicated team. If you only achieve 5-20 per week, that is a great start!
Always look for sites with a high PR; an audience who regularly interact with content, which often implies repeat visitors who will see your link time and time again; and strong unique content. You will often need to provide a reciprocal link on your own site so make sure you have areas where you can put reciprocals that do not detract from your site content and are useful for your website visitors.