All you need is a cheap black suit jacket. I got this one at Goodwill for $7. Some black or dark blue tennis shoes. A dark blue tshirt. And some white electrical tape.
Optional: large white weather balloon.
Step 2: Trim the shoes and the jacket with the tape
This character always wore the same getup in every episode: a black suit with a particular white trim around the edging and the lapels. black or blue deck shoes with white soles. That is all there is to it, it doesn't get any easier.
Work the electrical tape around the lapel and all the edges of the coat.
Wrap electrical tape around the soles of the tennis shoes.