1. I used his book. - Koristio sam njegovu knjigu.
2. I used a hammer. - Upotrebio sam čekić (You can also say: "Koristio sam čekić" but it is better if you say "upotrebio")
3. I use that website. - Koristim taj vebsajt (If you want to use a typical Bosnian word, you should say: "Koristim tu internet stranicu" but it is much longer and I know English people love to keep everything short and simple :) )
4. He used her to get on the baseball team. - Iskoristio ju je da poboljša/unaprijedi bejzbol tim.
5. I used up all of the butter. - Potrošio sam sav svoj maslac.
I hope my comment is going to be useful. If you have any further questions, feel free to ask me.