Here's a simple way that kind of follows the 80/20 rule. Make a list of 10 keywords that have good traffic that you want to rank for that is close to your core niche/keyword. Then, go through that list and pick say 3 of them that have the lowest competition. Take that list and pick the three pages on your site that correspond to those three keywords and build links for each one of them. That way you will build deep links instead of just links pointing to your main page. Make sure your anchor text matches closely to your target KW and you'll start to see results. Don't overcomplicate your link building. Just keep it simple and hit a few small goals at a time. Once you rank for those three keywords, move on to the next 2-3. Rinse and repeat. It works.