1.Each nationality is avaliable and has its anventure.You have to choose which line to lvl up.BB has strong firepower,SS is dangerous for all other ships but CV can bomb someone from a long distance.
2About BB.KM BB has the longest range,but the weakest firepower.US BB and MN BB own great guns but shorter rangge.RM BB's guns are easy to control.IJN BB is good to anti aircrafts and fast.
3About CV.MN planes have enough fuel,so they can fly longest.UK TB is magic.it can kill a BB5 in 1 second.US IJN and KM fighters are good to shot down planes.
4.There is no doubt that KM ss is best. IJN ss is special.We seldom use other "country's"ss.
5.Man,you must get a crew of elite  sailors at least.Super elite sailors are better.But hero sailors are best at lvl 125.
6.Different sailors need to be trained differently.U had better look the sailor tree  up in the GAME INFO on official website .
7.Supplement your sailors'  recruit every  time as they lvl up Right click mouse at RCT to do that.
8.A man need to learn how to AA.AAmeans anti aircrafts.AA can get experts.Experts can become veterans.
9.One can get most ships in the game with Credits.BB6 and cv6 are bought buy 50 Million credits and 20 Million points
10.It is easier for u to get your CV .I got my first CV when i was about lvl 40.CV can earn lots of Credits and Points.BB and SS is too difficult to get money.
11.It is necessary to buy a premium.u can get 180% EXP and more credits .It enhance the rate of Veteran . 

dear GM,i wanna got US ECV5.5.Thx!