Help with my teeth and toothbrush.?

ok i feel like the toothbrushes my dentist are giving me are junk cause i brush twice a day or more sometimes and every 6 months i come back and they say it doesn't look like you've been brushing and that is embarassing i'm a 16 yr old guy. Is there like a good electric toothbrush brand that is good for my teeth? if you know a good toothbrush brand whether electric or not plz tell me and what is the best paste brand, mouthwash, teethwhitening kit(if those even help cuz my teeth are somewhat yellower than i would like)