Trial and error?
Else get a program to analyze the frequencies produced and increase the frequencies that're already reasonably loud. It'll probably make other ambient sounds louder too. Not sure exactly what they are, i haven't bothered analyzing sound..
Yeah i know, probably not the most helpful response but it might help you in the future equalizing again
If you make the sound louder via an equalizer, it is probably going to distort which will make the sounds even harder to distinguish.
If you want to hear some frequencies louder then pull the sliders down on all frequencies except the ones you want to hear more clearly. If you apply your changes like that, there's going to be less distortion.
Are the footsteps more of a thumping type or is it a rather "high" sound?
As Zug was saying, you should start by placing all of the sliders to 0dB. Think of this as your baseline, where the frequencies are being neither boosted nor quieted. At this point, I'd agree that trial and error is your best bet. Take turns putting each slider up, say 5dB, making sure only one is turned up at a time. Then go into the game and see if you've found the right range. It might take some time but it should work!
Use the negative EQ method. Reduce the frequencies that you don't need, leave the range you need on the default 0. If you mean it sounds like crap is because of clipping, then that will help a little bit.