Impressing a Guy

I’m still a 19 year old girl, who seems to be sociable and gets along with people well. At present I have feelings for a boy. But due to a certain past experience it is hard for me to not think that things might not end well with the one at present. I fear I can become too clingy and I often find myself doing things only to make myself seem more “impressive”. I am trying to change these habits, but how can I make myself/feel like a better person so in turn, not repeat any mistakes made in the past, which would put him off (which is something I fear most)?