1 of my customers is a personal trainer. he gave me some advice. so i guess i can pass it on.

no soda
no fast food
low on carbs unless im going to go work out within the next hour
for me he said i need 3100 cals he had me do all kinds of test to figure this out) a day but in 6 meals (portion control pretty much)
never skip breakfast lunch or dinner
do some form of physical activity a day
when u work out never do the same thing twice in a week keep it changing so your body doesnt get used to the work out and adapt
whenever your working out and it starts to hurt but in a good way keep going and when u think u cant do 1 more do 1 more
whenever your working out and it starts to hurt in a bad way stop asap.