The key to seeing Wales flourish in this upcoming Euro 2016 is definitely going to Gareth Bale staying fit. 
Wales most potent attacking weapon and prolific goalscorer, Gareth Bale, scored over 5 goals during their campaign. Players opposing Gareth Bale will be well aware of how dangerous he can be in front of goal and would do anything possible to try stop him even if it means being in the refereeing card book.
Gareth Bale recently won the UEFA Champions League with his current club Real Madrid and has been in top form since then. Wales will be hoping he can maintain this top form he is in.