I guess it all depends on what you did to ruin your chance and how much this guy liked you in the first place. My advice would be to start building a solid friendship. Let him know that you are serious about having him in your life. Rebuild the trust factor and soon he’ll realise that you are sincere and that you now have feelings for him. Do, however, keep in mind, not to force anything. By doing that, you’ll push him away rather than get closer.