When editing video, you should strive to achieve the best video quality possible. That's because, believe it or not, some people actually don't like to see ugly videos.
It's actually not that hard to make something that looks somewhat passable. But yet, many people fail to even achieve this much. Here are some basic guidelines to help you improve your videos.
First of all, I recommend you read this guide hosted at animemusicvideos.org. It will teach you everything that you need to know about video. But, if you are too lazy to do that, follow on.
The first thing that you need to consider, is the source that you are making your video from. You need to start with the best source possible. Garbage in, garbage out.
DVDs or Blu-rays are generally the best you can get. So when possible, use them.
If you choose to use DVDs, then you really need to IVTC the footage most of the time in order for it to look correct. You can learn how to IVTC by following the previously mentioned guide. If you don't IVTC, then your DVD footage will probably look pretty crappy. In that case, it might even be better using downloaded footage.
I don't endorse using downloaded footage, but many people do use it, so I'll at least tell you how to make it look halfway decent.
First of all, if you are going to download footage, at least download some that doesn't look like crap. DON'T rip video from a streaming site like youtube or crunchyroll or something. That is just fail on so many levels. When people do this, I just wanna kick them in the nuts.
If you want downloaded footage, get it from torrents, preferably without subtitles. Look somewhere like nyaatorrents or even thepiratebay or something. If the anime is in mkv format, then it is usually (but not always) softsubbed. This means that the subtitles are stored in a separate stream, and are not physically embedded over the video. You can also look for raw anime. Raw just means that its the original japanese episode without any subtitles or anything.
Next, DON'T compress your video to something lossy before you edit it. This is just dumb, and it doesn't achieve anything besides making your video look crappy. Lossy codecs/formats include: divx, xvid, x264, cinepak, indeo, wmv, mpeg, mpeg2, mp4.
If you convert your video to something else before editing, then you should ONLY convert it to a LOSSLESSLY compressed AVI file. Again, the previously mentioned guide tell you how to do this.
After that, learn what a freaking aspect ratio is. If something is supposed to be widescreen, then here's a clue: its not going to look correct if you squeeze it to 4:3. Edit your video at the correct aspect ratio for your source. The aspect ratio of AMV Minis is irrelevant to your decision.
Don't randomly change aspects of your video like the framerate or resolution unless you know what you are doing. You are probably breaking it.
If you use windows movie maker, you fail. Get Sony Vegas or something. Movie Maker forces it to the wrong framerate, doesn't let you export in good quality, doesn't even let you edit with frame-accuracy, and I'm going to stop myself right there because I could keep going for a while.
When you finish editing your video, export it losslessly or uncompressed. Don't compress it with something crappy out of your editing software. Also don't let your software resize it or change the framerate. Try to export with settings as close to the original footage as possible.
DON'T export it interlaced. If your original source was NOT interlaced, but its interlaced after you edited it, then you set something wrong in your editing software. Fix it and export it again.
After you have exported it, you can compress it. You can use my zarx264gui tool to make it an mp4 [a guide for it is on the page where you submit videos]. If you prefer to submit your lossless video to me, I have no problems with that.
If you have questions, ask below.