Two things may help (1) Adjust the black point or bottom of the Curve (RGB) straight line can start where black starts; (2) Adjust Curve so contrast is carefully adjusted differently for different ranges -- darks, mid-tones, brights. A common technique to give a snappy contrast look is to add points to the curve at mid and quarter points then move the outside points inward slightly for a bit of an S-curve. That won't quite work with these pictures, but a bit of experimenting with more points and where to move them (with great care!) could work wonders.
My diagram is just an example and not quite right for what you need. I think Lightroom might also have a niftier way to use curves by adjusting in sections. There are reference pages on line. Give it a try -- I like what you've done so far and I think it is very possible to get the adjustment that will look the way you want it to.

The SteadePod is well-made and has the advantage of automatic rewind, locking at a desired length, strong cable, etc. I've used a monopod a lot because it is so portable and also intend to rig a way to fasten the SteadePod to the top of the monopod to pull against from one side for even more bracing. The homemade string, bolt, and washer also works okay and I had one years ago but got tired of winding it up and untangling it between uses. Without any of the above, I sometimes just brace against a tree, building, or whatever else is nearby.

Life is good -- there is a choice of great programs and plug-ins for using RAW as previous posts have mentioned. I like to have my Nikon save both JPEG and RAW and currently use the Adobe Camera RAW plug-in with Photoshop CS3. (1) The JPEG files are easier and more convenient to review and (2) preparing important shots for special treatment, opening the RAW file for any fine tuning before it opens in Photoshop is better for initial first subtle tweaks and corrections. Being able to adjust blacks and recover some blown-out highlights alone makes it worthwhile. It is kind of like having a negative that can be re-developed as many different times as needed for desired results. I am totally sold on using RAW files. They were a puzzle at first, but rapidly began to make sense as I used them.

Another alternative more readily available to Canon users than for Nikon is to use a good two-element close-up attachment that screws to the front of the lens like a filter -- the ones that are highly corrected for chromatic aberration. I've used the Nikon 5T and 6T on an older Vivitar Series 1 70-210 zoom (2nd Ed. Tokina) on a Nikon D700. A dedicated macro lens is sharper and easier to focus, but it is a versatile setup and the out-of-focus backgrounds are creamy-smooth. Some modern zooms would probably yield even better results.

I frequently engage in the folly of chasing insects using only natural light. Results won't match those from a classically super-sharp flash-lit approach and fairly high ISO settings have to be used, but it is possible to get desirable results and with more shooting freedom. I'll attach an example.