if you want to skip the grind:
just pick a BO and 2 gunners and do AA (when nation allows) or HH (when can't go AA ship) CL-CA-PCA.
Instead of regular supports for any CV/BB just lvl up some engys... when they are lvl 65 sell them. Repeat the procedure maybe 2 or 3 times. When youre' done you'll have a decent medium-high lvl BO and a nice pair of gunners (at least for seccondary armament) buy the sailors u need at the best lvl you can get (maybe something arround 70's to 80's)
this way you'll scape most of the grind, at least BB1 and most of the BB2 stage (for CV you will be able to buy something arround T3 when fighters start to be fighters)
OR:
put all of your crew (including powerlvling BO) above KM/RM AA ships, you'll end up with your entire crew at lvl 65 right after molke. it will not "skip" your entire grind, but it shure helps to dodge the BB1 lame-stage
final advice if you DO gind from the very first to the very last ship:
- CV1 and CV2 can only be used to BW, as they won't change much the balance of the team you will be doing more help bombing than using locals/T1. at CV3 you should consider using T2 and Scoutwhore, maybe doing something like 1 or 2 k of airplanes. this will give you a lot of xperience in micromanage.
- SS1 its quite anoying and SS2 can't play anything good but defense. a PCA of most nations will give you just about SS3 when things start looking good. just do that
- BB1 are trash for all nations, but BB2 are quite fun, with a decent crew you can be at about 600-700 SD at lvl 70. Besides nobody really cares what BB2 are doing in battle, so nobody will set you as primary target. Using that at your advantage you can put up 30-40k damage battles... if you do that you can have your fun while grinding