Drink lots of water, while dehydration isn't the only cause of a hangover, it is a major one causing dry mouth & dizziness.
Coffee and tea can also help you feel better, since they have caffeine, which can help you in getting relieved from headache.
Load up on carbs like bananas that helps to raise your blood sugar to relieve you from symptoms like fatigue & weakness.
Eat eggs since it contain amino acids like cysteine, which helps in clearing acetaldehyde produced after alcohol intake.
Hydrating with electrolytes helps in replenishing the salt and potassium in the body, which are lost while urinating.