Marketers can sometimes make the mistake of thinking the hard part is once they have set their Google AdWords campaign rolling – but according to one expert, the real work has only just begun.

Writing on online merchants’ site AuctionBytes, Jeff Gawronski said setting up pay per click marketing is the easy part, as the true test is achieving a return on investment.

"A good campaign is only such if it is profitable," he said.

One of the keys to campaign success is avoiding overspending, Mr Gawronski noted. This refers not to the daily budget for ads, but what marketers are prepared to pay for each click.

When starting a new promotion, it may be sensible to pay around $1 per click to ensure top placement in search listings. However, unless businesses are selling expensive goods or have extraordinary conversion rates, this amount will not be sustainable.

Nevertheless, as long as an ad is getting clicks, its placement will be largely unaffected if the firm reduces the amount it is prepared to spend per click because Google would rather have relevant ads that attract higher traffic at a lower cost than overpaying ads consumers are not interested in.

Figures from comScore showed Google accounted for 65.4 per cent of the US search market in January.

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