Like most have stated here a shower/bath should do the trick (some ppl need 2 or more a day) but try investing in fragrance that will compliment your natural scent (so it will not be overpowering)..if you can afford to invest in more then one, that's even better so you can switch up frm time to time but above all, daily bathing is essential.
Avoid dairy products, they make you have really bad breath like sour milk :P. Eating the carcasses of dead animals can putrefy in your system with no fiber to move along. Stinky inner body and outer bad smells.
put on deodorant once int the morning, once in the afternoon, and if your going out at night do. put on perfume every time you can like 3 squirts. i do about ever 2 hours. take a shower once a day. i take one everyday at night just because i dont have time in the morning. i do all of this even when i dont smell or sweat. oh yeah and when you go to pe or excercise change all of your clothes... including your underwear and other undergarments...... brush your teeth at least 3 times a day. i do all of this and its really quick. when i type it out it seems like a lot.
if you are a dude...use women's deodorant and perfume. i think it's so hot when a guy smells like flowers and fruits. but if you are a girl...please please please do not use boy's deodorant or...what ever they call their perfume.