Are you fighting mobs of too high level? Level difference is the overwhelming modifier in the calculations to hit/miss.

Are you using a rank appropriate weapon? Is it in need of repair?

Use Life Surge before you engage. Use Comrade in Arms, too.

You only need DEX up to about 80-100 points. After that it doesn't make much of a difference.

Other than that, you may just only be thinking you are missing more than you actually are.