• DO shop around and research search engine marketing companies before deciding on one. Make sure you ring each company up and speak to them in person. Just because a website says a company is based in the UK doesn't mean you won't be handled from an Indian call centre. Also, make sure you look around for reviews on the company or companies you are considering; people may have had experience with them that they have published on the Internet.

• DO get quotes if possible from a large range of companies before deciding on one. Some companies offer smaller packages to new or small businesses that would be better for you than taking on a larger package that you may struggle to pay for. If the campaign goes well and increases traffic and sales to the website, you can then decide to upgrade your SEM package with the company.

• DO research search engine marketing yourself. Whilst it's not advisable doing the work without experience and training, it is worth researching the work a company is offering to do for you. That way, you can listen with some knowledge when speaking to their sales department. There's a lot of wrong information available, however, so exercise caution and common sense when reading up on the topic.

• DO inform your web developer (if you have an external one) that you are going to employ a search engine marketing company. Your web developers may need to work closely with them depending on how much work is needed on the website. In addition to the list of Dos when investigating the possibility of employing a SEM company, it is also important to consider a list of Don'ts:

• DON'T attempt to undertake search engine marketing yourself. It is best done by a professional company whose expertise is in this area. If you do feel you want to try it, inform the SEM company you are working with first, as you may inadvertently employ techniques that will harm your site's ranking and performance.

• DON'T agree to spend more money than you are comfortable with. If a company is willing to write off your business because you won't spend above your reasonable budget, then forget that company and look for another. Whilst search engine marketing is a good method of advertising, it's not worth going bankrupt for!

• DON'T feel that just because you have spoken to a company and got a quote from them, you then have to employ their services. Remember, they have sales personnel trained to do just that, sell their services to you; with this in mind, don't feel pressured to take out a contract with them.

• DON'T sign any contracts before you have read through them thoroughly, including the small print and the billing information. You need to ensure you have a clear picture of what the company will be doing for you before you give them the go ahead to do it.

Always remember that, at any time should you be unhappy or confused about the work a SEM company is doing for you, you should feel able to ring them or contact them at any point to discuss your concerns. If they refuse to do this, or ignore your attempts to contact, it may be worth moving companies.