I have one legit website with 1+million on visitor's per month, but I'm still not ranked in google for a lot of keywords since my competitors have 3+ years than me and are getting better positions. Would you build some backlinks? I just have some "fear", because every one say that every kind of build backlinks = risk to get penalised. Ah, and of course I would do High Quality backlinks with unique content on Guest Posting, Private Blog Networks and etc. Thank you.