If your ads are not performing, try one of the following:
1) monitor the keyword referrals to increase your 'negative word list'
2) montitor the site usage of the referrals you get so that you can see if they all get to the same page / and leave your site
3) use an 'online intake form' and mention some kind of special "web only discount or deal" so that they are incentived to fill it out
4) once you have the above #3 in place, use a cookie or tracking software to monitor what word phrases give you the best conversion rate
Good luck.
If it involves shipping something to you for repair or whatnot, then it will be a little less, but can still be optimized, and one of my clients gets about a 1% conversion rate for this (up from .05% a year ago). Although, I've never seen a number for what is acceptible in this region, other than making sure you're getting an accptible profit.
The most difficult conversion rate is getting someone to leave their computer and walk into an office. We're still working hard to determine these types of conversion rates (as your goal is to get them into the office, so there are 800 number tracking involved, office surveys, etc) but they are only so accurate as humans and not computers are involved in the tracking process.
The one thing to consider with this is that most companies don't have physical offices that cover 100% of a population, so already you're factoring down the population that you can serve, so if you're in 40% of a country, suddenly a 2% nationwide conversion, becomes a .8% conversion rate.
It's this last type of conversion, I've never seen a number, or even a good article about. I'd love to hear anyone's opinion/examples about this type of conversion number.