Is there a way of speeding up thinking without diminishing the quality of thoughts?

I am and always have been a slow writer and thinker. I have thought about learning to touch type to help speed up correspondences and other activity online, but I think it might be my brain power that is more of a problem!

I don’t trust my initial thoughts and have to take time to digest and think things through at leisure. This is not always practical.

Is there a cure for being dull-witted? Are there certain activities or techniques I can adopt to help be a better thinker?