Online Promotion

Hi. May you please share some of the marketing strategies on how you promote your services online? Of course, we are active in Facebook and Twitter too just like other business owners. These 2 channels are great for increasing brand awareness and a good way of reaching out to your target audiences. On the other hand, I heard that G+ is good for promoting services, any idea? It's easy to create a G+ account but my only concern is that it's quite tough to get a lot of followers there unlike in FB & Twitter. Plus, Google is kinda strict with the way you promote your website (spamming issues). Can you suggest any other effective online promotions? Thanks.