How do I do my sister’s hair and makeup for her wedding?

My 18 year old sister is getting married in Las Vegas next week. She is on a very tight budget and I will be with her. She cannot afford to have her hair and make-up done.
I am proficient at applying make-up, I just would like some color ideas for a wedding.

Her hair is the big issue, she has thick shoulder length (no layers) dark brown hair. It is straight and reletivly easy to work with.

To give you an idea of her looks and coloring, think of Sandra Bullock, they could be twins.

Any help would be appraciated.
I should add that she is wearing a very simplt tiara and veil