Upload & Sell: Off
A couple of efficiency-based questions:
1. Does Aperture tag as the images are being ingested? If ingest and tag are two separate steps, you're wasting your time.
2. Personally, I don't see any point to deleting bad shots as an early step in your workflow. Once you've completed your process of selecting the various levels of keepers, what's left can be deleted. Thus, rather than identify and then delete the 'bad' images, spend your time identifying the ones that are not bad, then treat the rest as 'bad' and delete in one fell swoop.
With practice, you'll get to a point where, first time through, you can differentiate between keepers and non keepers, and within the keepers, top-, middle- and lower-tier. Obviously, being able to do this with one pass (your first and only pass through the images) is advantageous. Then, you work with your top-tier images and, if you need more, or if you just want to play it safe, go back through at least the middle-tier keepers to see if there are any you should have rated higher (just as, when you go through the top-tier to edit, you will find a few that didn't warrant that top rating).