I want to be stronger with doing bodybuilding (very big muscles aren't my target) without taking any sort of supplements .what food to eat and how ?

Protein/ H2O/calorie: Sounds like u r looking for strength & tone. Join a health club have a atc set up a program 2 meet ur needs. B dedicated, adequate hydration & protein & caloric intake. Gradually increase wt & intensity, take a day off, do cardio, & lift again the next day. Have a few 1 on 1 sessions so u have a good grasp of ur program. Have a sheet of ex & wts & keep a log 4 each day.