Nothing improves your handling skills like aeros do. But it's not by any means difficult; however, the basis for aeros has to be solid stick and rudder skills and understanding.
So, how to become an aeros pilot:
1)Do a PPL.
2)Ensure you have a good understanding of and can demonstrate good basic stick and rudder skills. You may have this immediately post PPL, you may require extra experience to consolidate skills to get to that state (I did), or you may require extra tuition to polish basic skills.
3)Enroll with an aerobatics instructor. Satisfy him/her that you are competent and safe in aerobatic manouvres.
That's it!