I find myself spending a lot of time with people who are not well enough prepared. I don't mind doing that, but it uses time that others might use for presentations. To fix that let's try the following.

Presentation grades will be 2 steps below the grade your presentation earns. So if your presentation is worth A- (because it was perfect but given on a date where the maximum grade is A-, it will be entered into the review sheet as B. 

You can raise your grade by helping others. If you help someone (and come with that person to his or her presentation), and if that person earns the maximum grade for that date, your grade will be improved by one step, e.g., from B to B+. (One important reason to come with a person you helped is so that if that person has trouble you can help him or her improve in that specific area.)

You may help multiple people. You increase your grade one step for each person who does a perfect presentation with your help. In the example above, if your initial grade was B and you help 3 people, your grade will be raised to A.

I'll keep track of these step increases by entering a ' after the grade for each step increase. That means it's possible to increase an A+ to a higher grade such as A+'. In the example above, the B that became an A will appear on the review sheet as B'''.

The limitation is that you are eligible to get credit for helping someone on a project only after giving a perfect presentation on that project yourself.

I know that all sounds fairly complex. The idea is for more people to come to presentations better prepared by getting help from others.