Updated Oct, 31st 2016
This class is suitable even if you are new to Adobe Illustrator. It's simple yet tedious so I'll recommend not to be too ambitious the first few attempts.
In this class you learn:
The basics of Low Poly Art
How to create your own Low Poly Art step by step
I'm sure you'll be able to create your very own poly art once you've gone through my class.
Note: As you can export the low poly art with transparent background as PNG, you can change all different sorts of background easily. Should you require any help to change the background, let me know. I can upload a procedure file.
Hit Ctrl + Y to bring up the outline, then you can see and start to clean up the triangles. My drawing is quite good so there is nothing much to clean up.
But I’ll teach you the trick to make all points align perfectly at the right position. It’s an easy procedure. With the Direct Selection tool, select each group of points that should be at the same place. Open the Align panel and click on Horizontal Align Center under Align Anchor Points and Vertical Align Center under Align Anchor Points.
It should align them perfectly. I’ll upload additional video within a few days.