As for advice for your specific case...
'Mastering' is often considered to be a 'dark art' that takes YEARS to lean, and can only be done with $100000000000000 studio hardware.
Many people will scoff at the suggestion of you 'mastering' your tracks yourself in a home studio... but being realistic, many people are now trying their best to get a DIY mastering/finalising process in their home studio.
If you're not even necessarily releasing the track, you might not want to spunk a load of cash on mastering, but you still want your finished track to sound as good as possible.
Here's the best advice I can think of for the DIY approach;
1.) Have your tracks hit your master output buss/track AS QUIETLY AS POSSIBLE. I now put a utility plug-in as the last plug on every track to reduce it's gain by 10dB, this way you can still use the full throw of your fader, but output a very quiet signal.
Once you've got your mix together on your output, it's very easy to make it louder, but not the same case to make it quieter.
Ideally, before you start adding processing to your output, you want the loudest peaks of your track to be no louder than around -6dB, any quieter is okay.
I can't stress how much easier this makes your life... typically, amateurs try to send every track as loud as possible... very bad habit, which does not help get your finished product any louder at all.
2.) Try to deal with any issues at a track level rather than on your output buss (as far as possible.)...EQ etc. Get each sound right in the first place, then finalising the track is easier.
3.) Get this free plug-in Bram.Smartelectronix.Com
... It will show you what your wave form looks like. Make it your last plug-in on your output channel, so you can see how you are affecting your music.
4.) Get this free plug-in Blue Cat's FreqAnalyst - Real Time Spectrum Analysis Plugin (VST, Audio Unit, DirectX) (Freeware)
... It will show you what frequencies you are putting out. Make it your second to last plug-in on your output channel.
5.) Hopefully if you've done point two here successfully, you don't need to do much EQing... however, you are going to want to cut of the highest & lowest frequencies; I will roll my low off VERY low; from around 15 Hz... but MOST people tend to do it from around 30 Hz. Whatever works for you.
I roll my highs of GENTLY from around 15kHz.
This will help solidify your bass end, remove frequencies that unnecessarily eat headroom, and remove harsh high end which could actually be painful to people on a dancefloor.
6.) Set up a compressor after your EQ, but before your metering (those free plug-ins.). Many home DIY mastering people seem to rate the PSP Vintage Warmer. Reading the manual is a great start! If you are unsure exactly what you are doing, the presets are a good starting point. Mix finalize 3 is a quite subtle, transparent setting you can try out. If you don't have VW, you can use just about any compressor in it's place. What you want is some compression combined with a brickwall limiter.
7.) Whilst watching the Oscilloscope as I recommended in point 3 above, slowly raise the output gain from your EQ (if it has one... if not, add a gainer plug-in after EQ, before compressor.)... driving your signal into your compressor.
You are watching for when your loudest peaks start to hit 0dB... therefore are being squashed by the limiter.
You need to exercise judgement here... the more you push it, the 'louder' your track will be... but at the same time you will lose 'punch' & 'dynamics' as you are reducing the amount by which your kicks are louder than the rest of the mix. Ultimately, if you keep driving it louder, your music will start to distort really horribly. So you need to use caution, but you should be able to reduce the loudest peaks of your kicks by a few dB.
If now you are starting to feel that it's not distorting, but you are losing punch of your kicks, you can pull back the gain that's driving into the compressor, then push the volume of the kick track a little louder in the mix.
A nice trick as a guide is to run a finished, released track you like the sound of through that oscilloscope, analyse carefully how loud the rest of the music is in between the kicks, then try to match your mix to have a similar balance.
There is no right or wrong here... you just have to use judgement.... which is why an experienced ME is worth shelling out for if you ultimately intend to release the track. Hopefully these tips can help you out in the interim though. Let us know how you get on ;-)