When you invest in Pay-Per-Click Advertising, on Google (Adwords), Bing or Social media like Facebook, Twitter, and LinkedIn, it's not about doing everything right. It's about doing everything a bit better then the others you’re competing with.
If you can't? Don't spend any Ad $ on PPC...
Here are a few tips on what it takes to win:
Realize you are competing with the Advertising Network itself first. Google will provide recommendations as to what to bid on and how to optimize campaigns, but at the end of the day, they will mostly help you optimize in ways that will optimize their revenues. Pro-tip, don't click all the defaults when you set up your first Adwords campaign.
Daily Optimization is key. Don't put any of your campaigns on autopilot. Don't allow the agency that helps you put anything on autopilot. Constantly optimize your campaigns. This is how you can find the edge to get to great ROI.
Constantly add negative keywords. Prune your clicks and make sure to learn from the clicks that don't convert to customers. Add negative keywords to make your target audience better and better over time.
The difference between making money with SEM/PPC campaigns, and throwing money into a deep pit is how you execute the final 10%. When you outsource this to an agency you should be especially mindful about this.