Very cool, I make music as well, and I'll be sure to follow what you post here. This is going to be a very long comment but here goes:

When it comes to flags, simplicity seems to be key, but most people agree that all flags should fall under these five categories:

1. Keep it Simple

Too much on a flag clutters it and makes it hard to spot and identify from a distance.

Japan has a beautiful, simple, easily identifiable flag.

Where as, the flag of Milwaukee is far too busy

2. Use meaningful symbolism

It should be representative, without question, and should reflect geographic, political, or national themes.

Ukraine's flag does this perfectly, with the yellow representing wheat fields and the blue representing the sky

The old Libyan flag is the opposite. Boring, doesn't share the pan African colors of many flags, or the pan Islamic colors.

3.Use 2-3 basic contrasting colors

Too many colors in anything can lead to poor design. When designing a flag, colors play a big role. They must accent each other without using too many colors or clashing colors.

Germany's flag has bold, distinguishable, colors that complement each other nicely.

Dominica has a pretty cluttered flag with many bizarre patterns.

4. Avoid lettering and seals

Flags, especially national ones, should be able to be viewed by anyone, anywhere and be instantly recognizable. Lettering alienates non native speakers, and seals tend to break the clutter rule.

New Mexico is a great example of representing its people and heritage without clutter or lettering

Wisconsin on the other hand has not only lettering, but a seal as well. Most US states have terribly designed flags.

5. Be distinctive or be related

Flags should either stand out vividly, or should show a common theme for its geographic region, political stance, culture etc.

Nordic Cross flags do this excellently. They all have the same design, but the colors and dimensions all have meaning.

Norway & Sweden

A bad example of this is Indonesia. Not only is it the same flag as Monaco, but also shares similar design with Poland.

Mind you, there are exceptions to these, but these are a good rule of thumb when designing a flag. Below are some that I have designed personally:

Based on England's flag and a Nordic Flag

A French-Swedish Colony

Combined the flag of the UK with Jamaica

Hope everyone had a good read!