Using EQ is the easiest, not-so-good way. However, when you boost low EQ to bring out the bass, you also bring out any kick drum that might be there. There are a few computer programs that attempt to isolate parts within recordings. But, frankly, none of them works very well. It's very difficult to isolate things once they have been mixed.
Fender P #913 - P&W Bassists #1105 - Wash. Bassists #81 - Greenboy Designs #101