Also Qel, could you give me any advice on playing the Cleveland? I was doing really well with the Ohama but moving onto the Cleveland I seem to get sunk so quickly. The most hits I've had in a game being about 50 whereas with the Ohama I was regularly getting 100+ hits and lots of damage in a game.
Keep in mind the last time I played it was in the Closed beta so they've changed the shell velocity since then, I think they now have a much longer arc and flight time.
For aiming you can only really get it through practice. At a distance perhaps try staggering your fire rather that firing a full salvo, at least until you get the lead on the target. Also make sure you have the alternative battle interface enabled (settings, controls, tick box near the bottom) as this will display the information shown when you hold down ALT all the time. The number on the left in sniper mode is the flight time to the target in seconds so this may help you judge where to aim.
Initially I'd try and stick close to battleships in a position where enemy planes coming to attack them will need to fly near/over me to reach them, but not so close to them that I restrict our movement options or have a chance of being hit by a stray shell from a battleship firing on them. I'd try and set battleships on fire from a distance but make sure you're not the primary target. You're tough but you don't want to get ahead of your allies and get focused. Once the two sides get closer I'd switch to firing on cruisers/destroyers as needed.
The Cleveland is the first US Cruiser to get great anti-aircraft capability and this can be improved through captain's skills and upgrades. Battleships will love you for escorting them and shredding enemy aircraft. Make sure you have the Defensive AA ability (icon should be a plane within a crosshair) equipped rather than Hydroacoustic as this will temporarily boost your AA fire and make enemy pilots panic so their torpedo or bomb drops are less accurate. Also make sure to Ctrl + Click squadrons in situations where there is say a Fighter Squadron and a Torpedo squadron incoming, this will focus your AA guns on the actual threat so you can kill the torpedo bombers rather than waste fire on the fighters which are no threat to you.
I'd mostly fire HE, at battleships and destroyers exclusively so. With lower tier cruisers and those +1 tier of you I'd try firing AP but only if they go broadside on to you within about 10km and try and get some citadel hits (generally aim for the shells to hit the waterline around the centre of the ship). The exception to this would be other Clevelands as their citadel can be hard to hit and you actually have fairly decent armour so I'd probably just fire HE to break their guns and set them on fire.
When facing other cruisers keep in mind that higher tier US cruisers and tier 5 and upwards Japanese cruisers have 203mm guns, these can penetrate your armour so angle against them as you would when playing a battleship. Many players will still shoot HE at you anyway but you don't want to chance a citadel hit. Against battleships aim for the superstructure/turrets with HE and try and present a small target to their huge inaccurate guns. If you set them on fire, shift your aim to another part of the ship to get another fire going.
For upgrades I'd probably go for Main Battery Mod 1 to stop your guns being knocked out so easily, AA Mod 2 to boost their range, for the third mod probably damage control but if your engine or steering gets knocked out often you could choose one of those, for the 4th slot Steering Gears Mod 2 for improved Rudder shift time, this will help you dodge enemy fire and torpedoes. Obviously this depends how easily the credits are coming for you.
Hope some of that helps, but I think once you get it fully upgraded and used to the guns you'll probably grow to like it. Once you're past the Cleveland all the US cruisers have 203mm guns as well so they should have higher velocity and a flatter arc again.