Don't be bashful! If you want comments, give comments. You don't need to be an expert photographer to express your opinion about the work of others. You don't need to go into great depth. A simple remark about cropping, composition, color, subject matter, etc. can be of just as much help to a budding photographer as an in-depth critique.
Shoot a still life using props for this assignment. Think about your lighting and center of interest. Use window lighting. Compose your best shot and use as many of the compositional elements that are appropriate for your subject. Once you get the best arrangement for your purposes, take your shots and post your best to the Web site.