As success is the completion of anything intended, I’d first and foremost make sure that you in fact aren’t already successful.
I gather from your question however that you aren’t, and therefore would suggest to start intending small things and see if you can complete them, like combing your hair or take your dog out for a walk. If you are successful at these, I’d suggest to move on to bigger things, like to paralell-park or be a host of a dinner-party.
Once you’ve made a habit out of completing what you set out to do, that’s when you can start calling yourself a successful person. And then you just go on from there.