There's one thing I find time and time again when discussing Adwords campaigns with clients, potential clients and people I meet in the street. Almost everyone seems to think that Adwords can operate independently of their site and that it'll all work just wonderfully from the word go, without any need to think about where the visitors are being sent.
Nothing could be further from the truth.
I'd estimate that about 50% of the success of any Adwords campaign is based in the website you're sending the visitors to and there are lots of aspects to that claim.
Firstly, there's the simple issue that your site may not actually be very good. It's tough to say that to a client but my word, I've seen some rubbish out there. The best Adwords campaign in the world won't help you sell beans if the site the visitors land on looks like it's been designed by a five-year old. A five-year old with limited knowledge of web design, that is. There's no simple way to solve this but it's always worth having a good hard look at your site from an objective point of view.
Then there's the products/services you're selling. Is it easy to find them, to buy them, to get more details. I've seen Ads that sent the visitor to the home page and forced them to navigate an impenetrable menu system to try and find the product they wanted to buy - that was advertised on the ad copy. In most cases, you'll want to send the visitor to the page specifically for that product/service. If you're advertising lawnmowers for sale on a household goods website, don't expect the visitor to find his way to the lawnmowers section, send him straight there, maybe even straight to the model advertised, if you're being that specific.
Then there's the technical side. We've all heard about the infamous 'quality score' and it's gruesome effects on CPC prices (and if you haven't you will soon on this blog). Part of the calculation of the quality score is an assessment of the site/landing page and you'll never reach that 'Great' rating without the site fulfilling all of Google's dreams. Make sure you refer to the Webmaster Guidelines when building the site or modifying it.
Most of all, do all this [i]before[/i] you start spending money on Adwords - or at least before you start spending a lot. Think of it like this. If you're selling your house, at what point do you do all the cleaning, decorating and gardening to make it look it's best? After you put it on the market, or before?