なに / なん = what
いくら = how much (いくらですか = how much is is? このとけいはいくらですか = how much is this watch?)
どれ = which one (use with が not with は – > どれがあなたのえんぴつですか = which one is your pen?)
どの + noun = which [noun]. Question word and also used with が. どのとけいが1000えん ですか = which watch is 1000 yen?
どこ = where (トイレはどこですか = where is the toilet?)
だれ = who (だれですか = who is it?)
いつ = when (いつが暇ですか = when are you free?)
どう = how (これはどう書きますか = how does one write that? どうですか = How is it?)
なぜ / どうして = why (その本はなぜつまらなかったんですか = why was that book boring?)
use 〜んですか instead of only 〜ですか if you want more of an explanation instead of only a short answer