These are mindmap examples pulled right from Google Images. You can look up more examples there, on Pinterest (those tend to be much more beautiful) , and I used the first two because they are from the creator of MindMaps, Tony Buzan, so they illustrate the correct use of the technology, with all it's research & relationships to results. Our alumni always do at least one complete mindmap "correctly," for the games they play, then use that to create them however they are inspired.
-different color branches for each sections
-words are all upright, for reading ease
-branches start thick and become thin
-plenty of images and symbols
-thought balloons for each section
-once you've followed the basic "rules" of mindmapping, you can add you own little things that trigger your memory and inspiration
Your entire mindmap can be drawn in theme. This one is so great.
-One word per section. Work with individual words, not sentences or even phrases.
It's tempting to use just words, but this won't work for the 20 Year Game. I take notes like this myself, because this is very similar to how are brains are actually structured, minus the images. And, in all the maps we've done, what consistently proves effective a year later is the drawings. The drawings are the key to bringing in the result. So if you are called to create maps in this fashion, that's great, just consider them an interim map, for clearing your head, problem solving, and fleshing out details efficiently. Once you've developed some skills in the fast-sketching department, you'll see your clearing, problem solving, and ability to create unprecedented, unexpected results magnify exponentially.
Once you've played with your map and have completed it by hand, it's perfectly wonderful and useful to create digital versions, minimal versions, graphic versions. They all serve to ground in the map usefulness.