Slope the ground away from the foundation. If you can plant grass to prevent water from standing. Divert downspouts away from the foundations with extensions, either solid or flexible.
LaToya: These help me -- a cheap fix
The most important thing is to make sure that your gutters are in good condition with no leaks and check to make sure they aren't clogged by anything (leaves, birds nest, etc). Build the ground up around the house and then gently slope it away from the foundation. Get gutter extensions especially if it's a hard surface that the downspouts are draining onto. We have plastic ones that bend to channel the water down our driveway.
Tar the base
The foundation made out of concrete are supposed to keep water, is it concrete or else...