I'm sure many of you already know this trick, but it's good to bring it up again as many people are complaining of being sandboxed. When linking to a new site, don't go after the broad keyword for your niche first. For instance, let's say your niche is "acne". Don't backlink to the keyword 'acne' just because it has the most exact searches per month. First, backlink to a smaller keyword... such as "acne remedy" or something that has way less exact searches per month. After you are ranking pretty high for this keyword, then start attacking the main keyword and Google will be way more receptive to your advances. I'm not saying this is 100% foolproof, BUT... I've sandboxed 3 websites already by going after the biggest exact search volume keywords first. But AFTER i rank a long tail niche keyword and then I attack the more broad/higher exact match keyword... I have NOT been sandboxed. This has happened to TWO websites for me already. So in my rankings.. 3 times I went after the big fish keyword, with most exact search volume, and got sandboxed 2 times I went after lesser keywords, ranked them within 1 month, and then went after the big fish keyword... and I have just been steadily moving up the rankings for the big fish keyword.