Making kick drum samples sound great when you do the mix down is something a lot of guys think is the answer. I've yet to witness a poor quality sample get mixed into greatness. Poor sample quality will likely be evident even after the mix. It's easy not to get caught up in this mess by trying a different method.
You can improve the sound a little by equalizing your kick drum samples – but that's about it. You simply can't expect to introduce something into a sound by equalization alone. The only way to get the sound you want is in the process of producing your track.
The best way to get a great sound is to start with one. You have to focus on getting the sounds right while you're creating your track. This is precisely the way to go about getting a killer sample sound each and every time.
The next time you sit down to work on a track, try using two different samples at once. The primary kick drum sample will act as the guide. You can then drop the second sound over the first one for some surprising results.
Alright so there is a bit more to it. Remember, practice makes perfect. Don't forget about using instructional beat making videos to illustrate these methods first hand. The quicker you learn these techniques, the sooner you'll know how to create killer kick drum samples.
Check out: Kick Drum Samples - for some great sounds.