How to increase the Quality Score in adwords?

I’ve implemented everything to improve the QS but couldn’t succeed. Website has enough of relevant content, ads are appropriate, relevant keywords are included in the ad copy, landing page is prefect, choose the right keyword match, even adwords team says that your ad campaign and landing page is perfect, so wait for two – three weeks. I’ve been waiting for more than two – three months but haven’t noticed any improvement.

Website is related web design, so the competition is quite stiff.

Few tips are available at:

http://www.redflymarketing.com/blog/10-ways-to-increase-your-adwords-quality-score-a-mini-case-study/

http://seo-kolkata.blogspot.com/2007/05/how-to-improve-your-google-adwords.html