Being active each day, helping each other and giving valuable opinions to others will give you what you need. Share your tips, your voucher codes if any and remember, don't be a miser in giving reputation to those who deserve them. Law of nature: More you give, more you get !
It is no different then how to get a good reputation in life. be helpful and kind to the other people here and don't spam
Just contribute. Don't worry about your rep. If your worried about it I'm sure your using it for the wrong reasons