Small businesses with a Google AdWords account are flushing away, on average, 25% of their pay-per-click (PPC) marketing budget because of easily fixable managerial and strategic errors.

That finding is highlighted in a recent study by the search software provider WordStream, which reviewed the PPC activities of 500 small and midsize business (SMBs).

The company graded those SMBs on various PPC tasks, including account activity, ad relevancy, keyword optimization, landing page quality, and mobile search, and found five simple changes that can help companies maximize their PPC marketing.

Here's a quick look at five tips for renovating your PPC advertising:

1. Follow mobile PPC best-practices. Fewer than 20% of AdWords accounts have created mobile-preferred ads. Make yours one of them.