I have been entering contests on this site for almost a year now, and I pretty much keep my opinions to myself. I do agree with Eve that a lot of the newbies seem to just cut and paste an image together and forget about the details.
The details I used to get ripped on when I first started (shadows, clean clippings, perspective, using 3rd party filters, etc.).
I have learned more about Photoshop in this past year by constructive cristism than anything else, and hopefully it is starting to pay off.
I am not really sure about the friend voting. I consider everybody on this site friends, and there have been plenty of entries of mine that Marco, Sean, Stephen, or Eve would not vote for because of something that needed fixing.
Honestly, like I have said before, the anonymous contests are the best. Here your work is honestly judged on the quality of the chop. Heck, I have received many votes through anonymous contests.
My advice to all your newbies is to study tutorials, like the ones on Splodges site
http://www.hallcross.co.uk/flash/SCROLL.htm
You can gain a lot of skill from these.
Listen to the old timers, remember they were newbies once. Also browse through their portfolios and see what a good chop is all about.
Don't just cut and paste and leave it obvious, keep it clean and pay attention to detail.
I am in no way a professional, but these are the tips that I have learned from my firends on this site. And I am still learning.
I hope I haven't said too much, but the most important thing to remember when doing a chop is to HAVE FUN!
Jim