Volleying and being hired is not the way to go about upgrading, instead have a look through the strategy section of forums. This guide explains how to upgrade and farm, I'd check it out first. Also consider joining a club, in a club you can make friends, participate in parties, and war. I would recommend that you party as this is the fastest way to make money, and therefore upgrade, until you can get max plunder (explained in the thread linked above.