How to customize a t-shirt?

I just bought some plain white tees - I wanna have like an 80s theme to it.. like
boom boxes, cassettes, colour blocks, cool shades, basically retro and vintage.. I wanna use sequins too! Got any tips??

well you could sew on the sequins
and for the 80's patterns, you should make a stencil
draw it freehand or look for images on the internet
cut them out and use some fabric spray paints
voila! 80's style customised tshirts