i would say that after Christmas sales start to slump dont you think? i find that you may have a better chance of sales depending what human habits you can think of. example after Christmas people want to loose weight and get fit. why not get some great shots of people exercising and running etc. in the gym is even better. these are targets i have set for myself. also think of easter - easter eggs,chocolate rabbits , little yellow chicks, it can go on and on. think festive and your a sure winner to gain more sales :)