Be aware of the subject in the frame, the availability of copy space and remember the rule of thirds. One issue I hear from buyers a lot is don't crop too tight, leave some room and let them crop.
For example in your Freerun photos, the subject is almost centered in the image. You have plenty of negative (copy space) above his head, but if you shifted the runner to the left (since he is facing/running right) you would leave a much better opportunity to put copy above him and in the area he is running towards. Make sense?
Your "Toasted Bread" shot with the open sandwich, in the future, clean up the crumbs on the table around the food in post if you have to. I prefer to catch them while shooting, but I've shot things like this and not caught those type things until opening them in Lightroom. Not everyone can edit photos themselves and that small detail could be the difference in a sale and bust.
I agree. People shots will always sell the best, but make shue the clothing is not dated, and the model is not too overexposed if you get my meaning. Watch the cropping. Make sure you leave enough space for advertising wording unless the shot is of the background type
I am a relative beginner too, but I would say that with your model, it would be worth taking some photos without glasses also, and with different accessories or clothing - if time is limited, maybe have a red hat as well as a white hat, that sort of thing. Gives buyers more options. Also different expressions - happy, angry, head in hands, etc.