Since there are no selections, I'm guessing this is a short answer.
Some challenges: accents, physical restraints, wardrobe malfunctions
How to help with accents: Taking classes and researching the accent
How to help with physical restraints: Exercise/weight gain and physical therapy
How to help with wardrobe malfunctions: In film, they can edit, but in live theatre it is best to improv through the scene until you can fix it
Hope this helps!