My test results...How do I improve?

[DJMorrisInc]

http://www.webpagetest.org/result/100609...4be7b7cba/ Here is a link to my test results....I am not appalled by the numbers, but I know I can improve and would love to get A's straight across except for the CDN one.

I have a caching plugin that I have added script to that caches all my pages and then clears the cache at midnight and re-caches the site....it takes about an hour for it to run through and cache all my pages, but it has made a huge difference. All this was done through script, hyper cache, and a cron job.

I would really like to make improvements, but have no idea....every time I try to add something to my htaccess it seems to shut my site down? Any input would be appreciated .