Iām just starting this audiojungle trek. I got my first submission accepted and sold within a day, only one sale so far 
I would recommend to listen to the top selling tracks and get the trend of what is selling nowdays. seems to be like ostinano arpeggios, guitars and piano, revolving around 120BPM, very organic with a touch of some electronic music builds. Looks like ukekele and claps and super happy is not very trendy no more.