AC has this little feature in the site called AMV of the Month. That's where I post good AMVs I find in YouTube/DailyMotion so that they can get more recognition. The past few months, I've been having difficulty finding GOOD ones... and have been seeing really
ridiculous ones.
So... for me, exactly
what makes an AMV/GMV good? Here's my take on the matter:
*
Note: All image examples done here are done by me. I will not point out actual AMVs that are... ugh.
1.)
Timing 
I see what you did thar...- I consider this a BIG thing. In some AMVs, timing makes EVERYTHING. Let's just say, you have a really upbeat song... I don't like seeing slow scenes coupled with the fast parts that song. Neither do I want to see fast/fighting scenes coupled with the slow parts of the song. If you can time parts of the video to even the instrumental part, then try to do so. If you're having trouble deciding whether to time that one scene to the lyrics or the melody (sometimes it happens), then choose whichever, and on the next part with the same problem, choose vice versa of what you just did, for variety. Do
not put big heaping chunks of a video (hello 30-second clips of a video you didn't even cut) with the song
unless it
really fits the song. When I browse for AMV of the Month, and I notice that the video isn't timed properly for the first 30 seconds, I disregard it =\...
2.)
Effects aren't everything
Just WTF am I supposed to be looking at here??- It's swell and all that people are learning to use difficult programs like Sony Vegas and Premiere Pro... but some people get waaay to overexcited with the new found possibilities... to the point that their videos don't look good anymore. Black and white scenes? Fine. Fade in/fade out in white/black? Totally fine. Split screen? Fine if in moderation. Overlayed videos? Again, fine if in moderation. But overlaying about 5-7 videos/images over another one, and doing it in
every single scene just makes the video too busy, and in my opinion, revolting. How about flashes? Unless your motive is to blind your viewers, then don't overuse them. If you have a part in the song that has a lot of beats, like,
a lot, then I suggest just using the black fade in/fade out and not the flashes. And for the love of... don't use that stupid black/blue/green screen effect every single time you see the chance to! Videos that abuse effects only strike one question to those who have a keen eye on observing AMVs: "
What the f*** am I supposed to be looking at here, anyway?"
3.)
The song's meaning 
At least make sure the AMV... makes sense.- Okay... so you're going to use a Japanese song... Not knowing the language is
no excuse to not make the video at least fit the song's meaning. And I'm not saying line by line meaning. Line by line meaning is fine, but not if it's used too much. What I mean is... you're using a song about... let's say, this world... This WORLD... and you use scenes that would fit a love song more... -facepalm- There is one thing that can make up for this... and that's timing. If you did the AMV mainly for timing to the song... then at least make sure it's properly timed.
4.)
Those picture slideshows
I see what you did thar part 2 - Slideshows are fine and dandy. Adding those zoom in/zoom out effects alternately actually does it some good. Not adding effects at all also does it some good.
But! At least, don't put a single picture for around, 30 seconds of the song or so. That's a waste and an insult to the song.
5.)
Intro Videos 
Short videos make the best intros.- Some AMV makers feel the need to make an "intro video" portraying that the AMV was made by them. These things are okay... But come on. Your intro video is 30-60 seconds long...
Imagine the trouble dial-up users have to go through just to watch your AMV.
Imagine the frustration of AMV watchers as they see a 2-minute AMV, with only 1 minute alloted for the actual AMV. Whenever I see AMVs with such a loong intro, I skip them.
6.)
Credits - Should go at the end of the AMV.
Period.
In conclusion: AMV-making is
not simply grabbing a bunch of clips and putting them together. It's an art, as well as a hobby. All people can make GOOD AMVs, all it takes is practice, and the understanding of what makes a GOOD AMV.
*sigh* I wish I could make AMVs... it's like fanfic, I have a few good ideas, but lack the skill to realise them...