Increasing intelligence?

Are there any proven or semiproven ways to increase the human brain's fluid intelligence? Thanks.

One's capacity for intelligence is a combination of genes, physical and mental health, and education. You can't help the first component (yet), but the others combined can more than make up for the first.

1) Proper diet and exercise. Seriously. It's been shown that a healthy and active body results in major improvements in brain function against every single benchmark.

2) Supplement your diet with a good multivitamin. Unless you plan extremely carefully, it's damn near impossible to get everything your body needs every day. I like One-A-Day Maximum, simply because it's easy to find where I am. There are some better ones, but you usually have to go to specialty stores/internet to find them and they tend to be a bit pricy. Do your own research on the specifics. Also, even though there's still some debate and evidence in both directions, it's a good idea to supplement your regimen with a strong dose of Ginko Biloba and the Omega-3, Omega-6 and Omega-9 fatty acids. Oh, and while I'm at it, you'll probably want an extra boost of Calcium and vitamin D (which improves absorption of Calcium).

3) Educate and culture yourself. This is a long, lifetime endeavor. Two or more hours of your day should be set aside for personal education, in addition to whatever formal education you are currently enrolled in. Get into Philosophy and Logic, for starters. It may seem dry to start with, but it really does change the way you think about everything. Likewise, a familiarity with basic Economics, Global Politics, and World History would do wonders. Basic Math (through Calculus, at least) is a must, and at least a High School level education in the major Science branches (Physics, Biology, Chemistry, "Earth Science"). Other than that, just go wherever your interests take you.