Depending on the shot I've been using the crop tools, lens correction, and in some cases the auto tone and white balance. Most of the time I'm one or more of the presets.
That is what makes LR so great - how flexible it is to your individual workflow. Since I've upgraded to version 3 and the lens profile feature, I've never used (or even installed) presets! Too funny.
My process is usually as follows - but this is maybe appropriate for 75% of the time. Usually I'll have an idea what I might want to fix first (crop, white balance, etc.) and I'll start there. Not all steps are taken everytime but this is the sequence that I generally follow.
1. Review histogram.
2. Review lens correction. Adjust as necessary.
3. Determine if color is correct. If not, adjust white balance.
4. Determine if the image needs to be lightened or darkened. Adjust Exposure, Recovery, etc.
5. Tweak tone curve if needed.
6. Apply graduated filter and/or spot adjustments.
7. Determine if the image needs to be cropped.
8. Determine if the image needs sharpening.
Hope this helps!