Assuming you're using a geny style rba, high vg juice will not wick nearly as well as high pg. If your using high vg, try creating a straw-type wick with a hole in the center... by rolling it up around a straightened paperclip or the like. Also, while it is not the case 100% of the time, as some setups can actually wick too well, it is typical to have to tilt the pv upwards when
vaping while keeping the air hole facing you, letting gravity aide in the wicking process while you vape. Often, I'll keep the pv tilted while I'm just holding it to keep most of the wick submerged between vapes.
You can also try using a thinner diameter wick, as a wick that fits very snuggly in the wick hole can inhibit the atty's ability to 'breath', and create sort of a vacuum which inhibits juice flow up the wick... or even choking it off outright if it's very tight. Good luck.