Need a little help

Does anyone here know of any good ways to get the perfect scan for a drawing? We have a new high quality scanner and i still cant seem to get my drawings to come out good, ive messed around with the scanner, messed around in photoshop, nothing.

Thanks in advance guys,
Chris.

I always turn the resolution to 300 dpi for my scans and use a bitmap image. If it's too light i'll play with the gamma correction and it makes the darks stand out more.
Original
http://img363.imageshack.us/img363/6797/worksketchesresize07dy8.jpg (http://imageshack.us)
http://img363.imageshack.us/img363/6797/worksketchesresize07dy8.d9b374ad8b.jpg (http://g.imageshack.us/g.php?h=363&i=worksketchesresize07dy8.jpg)
Slight gamma play around
http://img362.imageshack.us/img362/3470/worksketchesresize07gamoi9.jpg (http://imageshack.us)
http://img362.imageshack.us/img362/3470/worksketchesresize07gamoi9.160b696e5a.jpg (http://g.imageshack.us/g.php?h=362&i=worksketchesresize07gamoi9.jpg)
Hopes this helps you.

scan it n post it. lets take a gander at whatchu got. i have a few scanners layin around here never had this sort of issue with n-e of them.

ive done a few, heres what i mean:

http://img84.imageshack.us/img84/4541/drawing006iw4.jpg
http://img84.imageshack.us/img84/9725/drawing002ke4.jpg

http://img356.imageshack.us/img356/6641/drawing005vr7.jpg
http://img84.imageshack.us/img84/2771/drawing001pu2.jpg

I put up a photo for comparison as to what it should look like.

I just relised the bottomr one, the car is photoshopped to the "normal" scan it took, and the background is made white using levels.

The other one though, much of the smoothness and detail has been lost!