I Hate Being Shy and Having People Think I Am a Snob

There's a person that I miss talking to. I want to start a conversation with them but I'm too shy to do so. I keep thinking what if I end up wasting their time because I couldn't keep the conversation going? Plus I don't know how to start a conversation, or how to make it seem interesting. I just really liked talking to this person and I want our conversations to last as much as possible.