How to: Choose a Sweet Watermelon

Just recently, I bought a watermelon from the hypermarket and to my dismay, it turned out to be watery but bland in taste. I had been trying to figure out how to pick a sweet watermelon for ages now and it did not occur me to to just Google for the answer... until now that is. Here's what I found out:

Colour
It should be dark green and good contrast between the stripes.

Skin Texture
Should be solid and no part of the melon should be soft or mushy. The area where the melon sat on the ground should be yellow. The more yellow it is, the more ripe it is.

Sound Test
Thump the melon. A watery melon should give off a good deep "thump".

Dry Tail
The stub of the melon should be dry. If you are able to use your thumb and break off the stub, it means that melon is ready to be cut.

Appearances/Shape
Choose a watermelon that is free from blemishes, cuts, scratches etc. Also, the shape should be round and consistent. Odd-shaped melons tend to have inconsistent sweetness.

The Sample Test
Sweet watermelons tend to come in batches. If one is sweet, chances are, the other will be sweet as well (just how much or less sweeter, that's all). So if the vendor has a sample for test, it will be the best indicator whether the watermelon batch is good or not.

Finally, I found this video to be quite helpful:
http://www.wonderhowto.com/how-to/video/how-to-choose-the-perfect-watermelon-204716/

Mind you, I have yet to put these theories to test. Will be doing it soon. Please feel free to feedback whether these tips helped or not.