And if you want to see how I build the rest of the costume - tutorials here.
Starting point: plain wig
Then I cut off the hair on the left side (from Vi's perspective) and dyed the hair brown using acrylic color. The back and side is styled using hairspray.
But it still looks like you cut and painted you wig, the hair gets stiff and the wig net might be visible. And from the in game model you can see that the side cit is trimmed very short.
Screenshot from lolking.net
After using the wig once I found out I could make the side cut much better by using brown wool and needle felting. Needle felting means that you use a needle with tiny notches and you pin the wool several times until it gets compact (felted).
In the picture below I have added wool directly onto the wig and felted a small area where the needle is located.
Fully felted. I might blend in some more color to add some depth to the side cut later.
(letting the pink show trough just a little bit)
For the dreads I only used the pink extensions first and I tried to section them using hair products. This did not work so well. So why not needle felt these too. And they looked so much better after felting pink (with some small sections of deeper and lighter pinks) wool around the extension.
Extension attached to wig (The color looks a little off in this picture due to different light conditions).
Pink wool and needle
And the ends of the dreads looks better than just straight cut off extensions.
Many of you have requested more info on how to make the dreads or how to felt. Here's a small (vertical :S ) video demonstrating one way to do it.
First test with goggles, purple lenses and newly styled wig.
(not very purple effect from these lenses)
(And I need to make it fit my face better)