I realized recently that cymbals need to be mixed much lower in the mix than what you would think. A-B your mix with commercialy mastered mixes and focus on the level of the cymbals and how they're EQ'd. Try rolling off the lows too with the ProChannel EQ. Also don't pan the cymbals too wide as this will sound artificial. Hopefully this will help you achieve more realstic results. Best of luck and have fun making music!

I was at a studio where Vicki Genfan was working, and the engineer there (Sharon Stone - no, not that one, but credit where credit is due) played back some super-realistic sounding drum parts. Her stupid simple secret: Playing real cymbals on top of electronic drums. I've appropriated that trick several times, and it never fails to add a really "live" vibe.
 
If you have to go electronic, I think the Zildjian Gen 16 Digital Vault cymbal sample pack is outstanding. It's not cheap ($179 at Musician's Friend) although I have seen it on sale for under $50 as part of special promotions. It's also included in the Yamaha MOTIF 10th Anniversary Special Pack, which is no longer available but I saw one on eBay for $60.

For hi-hat and cymbal, you might try the Sonar FX Chain called Hathelper.  It gives a nice, crisp, thin sound.
 
For performance, as said above, velocity is important—and that applies to shaker and tambourine as well.  For example, for 8ths or 16ths in 4/4 time, you might try velocities like 80-60-70-60 or a variation, the idea being that the downbeat is the strongest and the off-beats are weakest.  You can do a section manually and then copy it, or you can use Find/Change to set the velocities by tick.  Example: if the clock is set to 120 and you are doing 16ths, you would use find change to set everything to 60; then set everything on tick 60 to velocity 70; and everything on tick 0 to 80.  If you clock is set to 960, multiply all these tick numbers by 8.  If you are doing 8ths instead of 16ths, just get your calculator out.  I always use the same clock value so I know off the top of my head what tick values represent which notes.  Some people make the difference between the loud and soft hits bigger (for example, 90-55-65-55), but I like it to be subtle.  A lot depends on the style of music, too.
 
^^This^^ assumes you are handy with the Find/Change command.  If not, let us know and we can help.
 
You might also use quantize and set the swing to something barely off 50%, like 52%.  I personally like things tight and normally just use velocity to humanize, but a little swing humanizing can help.
 
If you have a virtual drummer with sample MIDI grooves (like EZDrummer or Session Drummer 3), you can look at a MIDI pattern to see what was done.  You may find the hi-hat in these samples to be quieter than you like.  I am not sure why.

If you go to soundcloud.com/bill-hartmann, you will find some of the songs from a musical comedy I wrote—mostly funny songs and a couple of serious ones.
 
The song called "Don't Say Forever" has a shaker in the second half of each chorus that uses the techniques described above.  See if you think that sounds natural.  It enters for the first time at about 1:15.

Good Samples and Velocity settings.... Very important!

Another thing you might try is keeping the kit cleaner by avoiding hi-hat and snare together. Listen to Charlie Watts (Rolling Stones in case that doesn't ring a bell). Typically, he hits snare on 2 & 4 and HH on the eighths in between, but avoids HH on 2 & 4 with the snare.