Can anybody tell me how to go about 'texturizing' the top of my hair for volume?

If the top of your hair is thin, you can add a few layers to give it some texture and volume. I do not recommend that you cut your own hair, you might ruin it. Let a hairstylist or someone who is experienced cut it for you.

Pretty lady you did not tell us how mcuh hair do you have , is it fine ,medium, or thick? Well i would advice that you section your hair around the crown and twist all the hair as much as you can and then cut it with desired lenth slding the scissors and wallah you got your volume!!

Lovely lady