Just as we say 'able to do', we also say 'have the ability to do'. Both the adjective and the noun are followed by 'to' and the infinitive. If this is something that you are not currently able to do, you'd say this: "I'd like to have the ability to stand in front of a large audience and speak freely and confidently."

What I'm going to say may be out of place but is meant to teach you something you might not know. If you have a perfect ability or proficiency at something, you can say "I have a knack for... doing something." Jimmy has a knack for driving me nuts. Jenny's got a real knack for the piano.