Thanks for the advice, but I don't know how to tell the maturity of a wasp. As for its sex, I would assume that a wasp gathering prey would most likely be a female providing for a nest, but with my track record here for identifying wasps (and all insects for that matter, even telling bees and wasps apart), I'd probably only supply misinformation, which I'm certain wouldn't help anyone identify anything. (I've been photographing bugs in general for only about a year, dragonflies and damselflies for just over 2 years - sexual differences, turns out, are pretty easy for Odonates, though I'm still having a bit of difficulty with maturity.)

I am, however, very open to learning identifying characteristics for all kinds of bugs. Any suggestions, other than a college degree, on how to make educated guesses?

I agree that in most cases it isn't easy to tell the sex but when an expert mentions it you can add it to your entry. There are a few clues if you are interested in reading some tips.
Adult vs. immature is extremely easy in most cases (somebody should write an article). A very crude rule of thumb for a large number of species: if it has wings it is an adult. If it looks like a maggot, caterpillar, grub or a pupa it is immature. That takes care of about 80% of the insects that you find. By all means, leave it blank if you are in doubt (spiders, millipeds, wingless insects), but trust me you know more than you realize.
You have an advantage over me when it comes to Odonates; I know nothing about them.

Great article. Thanks for pointing me to it. It explains a lot. Since I'm attempting to get accurate photo identification of every bug I find in my yard (an overwhelming task, to be sure), I've bookmarked it and will refer to it often.

With Odonates, I've found that coloration also has much to do with sex and maturity identification. Is there something similar to coloration changes for identifying the maturity of other bugs? For example, an immature male Common Whitetail Dragonfly has male patterned wings with a female colored abdomen; when mature, the male's abdomen turns white.

Only recently I learned about this quirk in Odonates terminology. Technically all winged individuals are adults, whether they are called "immature adults" or just adults. They emerged from their last molt; they will grow no further nor have any more molts. The true immatures are the aquatic larvae, without wings. So, your "immature male" Common Whitetail Dragonfly is truly an adult.
In other insects the young adult with pale coloration is called "teneral"; this is less confusing than with Odes.