How do I tell a girl I like her without jeopardizing our friendship?

Basically what everyone else is saying is right. Just nut up and go ask. Be confident about it, but also be ready to handle a no and then keep on as if nothing happened. Also don't ask if you can date, instead go ask something like "Hey, when are you free next, want to grab a drink or get coffee?" Keep it natural, keep it simple, but most importantly, keep it to just the two of you. If a yes happens, cool, let the thing happen. If it goes well, before you part, ask if you can do it again in the near future, make it clear that you are looking to do more one on one things and then let it all progress naturally.