actually, the first step is to eliminate the leak. your foundation wall was designed and built to be a water tight structure. (if it was built properly.) is it a concrete (cinder) block wall? or is it cast-in-place concrete?
first you need to locate the source of water intrusion and eliminate it. it could be a pinhole leak, a man-made hole or leak (e.g. a hole for utility lines), a crack from settlement, or a crack from earth movement.
hydraulic cement is incredible stuff! google it.
secondly, divert water away from your foundation with french drains, scuppers, etc. this can be complicated, since everywhere on earth is a watershed, and it is illegal to simply divert water onto your neighbor's property or into the public right-of-way. (there are exceptions to the latter.)
also make sure the tops of your perimeter drains (the trench full of gravel that surrounds the bottom of your house's foundation) is clear of debris and vegetation. rooting plants should be planted a minimum of 2' from your foundation walls, and trees should be planted no closer than 8' - and away from utilities - depending on the size of the root structure.
and if you do it yourself, remember to call SPU before you dig if you need to locate utility lines.