How to increase fps in minecraft?

Hi, ive been wanting to play minecraft but its been more unplayable as updates come out. Currently i have optifog and optimine installed on minecraft 1.6.6 on my netbook and i only get 12 fps if im lucky and 7 on average. However ive noticed im only using 60% of my cpu and 50% of my ram. Is there anyway i can increase this?