I've got a few friends and colleagues who smell. One of my colleague smells bad even after a shower. But in a way, it's kinda pitiful for him because I think his blood has got toxins which his body can't get rid off. He's previously also suffered kidney stones. Now, the skin of his palms (front and back) is starting to crack and peel really bad, like dried mud. And now, his feet is suffering from fungal attack, which may require surgery if it doesn't heal with the special cream he's applying. I've told him direct in his face politely about this and gave him some advice but he just laugh and took it as a joke. I never mentioned it anymore after that.
Another one of my female friend had bad breath. I sms her and told her about it politely. She started taking mints after that. And somehow, her breath is better now.
For mouth care, I've tried various tooth paste and personally, I find many of them kinda useless. To me, Darlie and Colgate is not something I would go for. I use Fresh N White, the green one. With a good amount on the tooth brush and a good few minute brush, it could actually make the breath smell like mint. Else, could also try mouth rinse like Colgate's or Listerine's. However, take note as I've heard that regular use of those mouth rinse is not very good for the gums and teeth. Have not got a confirmation on that. In any case, I use it only when I need to meet girls. buahahahaha
As for body odour (body smell), I guess I don't have it unless I sweat a lot. In any case, smell or no smell, I always prefered to use dettol soap. Maybe it's the medicinal like smell that makes me use it but the new dettol soaps now a days are just "Mildly Medicated" where the smell is not really strong anymore. I guess one good way to control body odour (known to my friends as Calvin Klein 2 @ CK2 hahaha) is to bath with medicated soap and then finish off with fragrant soap or fragrant body shampoo, like Body Shop's products, etc.
Else, if all else don't work, spray on some flammable fluid and light up! Burn `em germs away! hahahaha Just kidding y'all.