How often should i shampoo my curly hair?

i have curly hair kinda like this if i let it get long enough--a href="http://www.whoateallthepies.tv/frodo_sweet.jpg.w300h456.jpg" rel="nofollow"http://www.whoateallthepies.tv/frodo_swe…/a now i was wondering how often should i shampoo and condition it to keep it looking like the picture up above ^^^ or what products would be helpful? i condition it every night with some good conditioner from the Bed Head brand for curly hair and i use some tresemme shampoo for dry or damaged hair. i condition it every night and shampoo it every other day. does anyone know how often i should shampoo and condition it to get it to look like the picture above and any good products you could recommend pls i really need help im starting to get to the point that if i cant find a solution im just going to start straighting my hair. i have before and it looks good but i don't want to have to go through the trouble in the mornings to straightin it but i have to go with what the girls like and frizz is not one of them so pls help thank you.