analyse and improve conversion rate

site is well optimised and positioned well in serps, conversion rate has fallen over past year and is presently abysmal. i would like you to look at both sections of the site, people finding and messageboards, and find a solution to converting at least 1% of visitors to enquiries, or in the case of the messageboards maybe 0.5%.No major redesigns wanted, i am sure the answer lies in simple changes, maybe some copy changes, redirection of visitors. This site has enjoyed visitor conversion of 6% 2 years ago, surely 1% is realistic