Don’t buy links.
Don’t sell links.
Don’t sell your content.
Don’t deceive your visitors.
When publishing online you have a responsibility to be honest. Anyone can get paid a few dollars and get a bit closer to the Most Crap Gadgets When You Die award thanks to it by selling out, but the damage done is way more serious.
Always mark ads as ads.
Always disclose sponsored posts.
Always separate content from paid content.
We have not fallen so far from grace that we view content as lies first. The initial reaction to something we read online is still that it is to be trusted. Questioned sure, but new sites are not automagically thought to be factories of lies. That can change, because every time we are deceived, we trust a bit less.
Never sell out.
I get it, you want to make money. I really get it, making money might even be why you publish your site. But that doesn’t mean that you have to be a liar and a cheat. Sell your ads to trustworthy companies, be clear with what is really an ad, and don’t sell out and deceive your visitors for monies.