I've tried all the Tier 1, 2 and 3 warships from each faction and class, and here's my 10c on all of them.
All the rookie ships are gunboats and are pretty evenly balanced. Pick what looks cool, though remember only USN and UJN have the full range of warship classes, so I'd focus on upgrading those first.
Not even a contest. The Umikaze and its 7km torpedoes is better than most Tier 3 ships and is the best ship in this tier, period. The Sampson's torpedoes only ranges to 4.5km and the Storozhevoi packs a whopping 9 torpedo broadside but suffers from a crippling 3km range.
They're all quite solid. The Dresden has masses of machine-gun-like light guns, and the Chikuma is speedy and elegant. I also did well in the Chester, but it is less interesting and unique in feel, so it got sold.
Again, rated nationally in the same order as Tier 2 - Wakakaze has the best 7km torpedoes, with the Wickes having acceptable ones and the Derzki very powerful albeit at suicidally short 3km ranges which make it very 'situational.' I.e. there's only rare situations where they can actually threaten the enemy team.
The St. Louis is slow but packs bucketloads of guns, able to slug it out with the awful Tier 3 battleships. The Tenryu is the first cruiser with torpedoes and acts like a big destroyer. Both are fun and offer very different playstyles. I disliked the Kolberg which seemed identical to the Dresden - only fighting tougher higher-tier opponents - I couldn't wait to ditch it.
I'd say South Carolina over Kawachi but it's like choosing chocolate or strawberry-scented turd pancakes. The slow firing battleship guns track slowly, are short ranged and inaccurate, and their lumbering bulk makes them easy prey to destroyers. They require even more forward planning than other ships, but sadly I notice they tend to attract the most brain-dead players who either yolo into the enemy solo and die or alternately sit sniping ineffectually at extreme range, or head down narrow straits where there is no room to dodge a torpedo spread. "Imma be a big battleship hurr durrr."
Crew Skills. You can "customise" your commander with special skills. Which skill is best? Depends on the ship class. There are five tiers of skills but I am only familiar with the first two.
Battleship = Basic Survivability +15% better repair time
Cruiser = Basic Firing Training +10 % rate of fire
Destroyer = Situational Awareness - indicates if ship is detected by enemies
Battleship = Aiming Expert + 2.5d/sec better turret rotation
Cruiser = Aiming Expert or Torpedo Expertise
Destroyer = Torpedo Expertise +10% faster torpedo reload
Beginner tips I learned from hard-won experience
View range matters. Destroyers are spotted around ~6.5km, cruisers at ~10km, and battleships at 14km+ (individual ships vary). Firing your guns increases this a lot (i.e. by 3+ km on a destroyer). Corollary: if you're a destroyer, you have a view range advantage - so don't fire you guns except as a last resort. Not being seen at all is the best way to (a) sink other ships (b) avoid being sunk yourself. In later levels destroyers have automatic AA - turn it off with "P" to avoid gunners giving away your location.
Firing Torpedoes. This is what makes destroyers feared. Press X to get a grey "predicted path" which shows where to fire to get a hit if enemies continue on their speed/heading. I tend to fire one salvo along this path, then a second salvo behind this path. If the enemy ship detects the first salvo it tends to swerve into the second. Delaying 1-2 seconds between salvoes creates a crossover "X" pattern which is harder to dodge. It's always best to fire at a target's broadside. If you're confident of your aim against an easy target, press '3' again to fire a narrower spread to land more hits on him.
Note: Sometimes players blind-fire torpedoes randomly down narrow straits as "area denial." Unless I am capping a flag, I don't want to "deny" them. I want them to enter the strait, then fire into it and sink them.
Corollary: Know your torpedo range, and know your opponents' torpedo range. Tip: The wide end of the green wedge shows how far yours will go.
Corollary: There's no such thing as a friendly torpedo. It's always on you. "But he swerved in front!" No excuses. You pull the trigger, it's your fault. Check your surroundings, check the minimap. Never fire if there is even a 1% change of an ally crossing your torpedoes path.
Dodging Torpedoes. Always try to run parallel "through" the torpedo spread; turning away from the firer gives you more reaction time (recommended - also sometimes you can outrun the torpedo), though turning into the firer means you can better hunt down the little bastard who fired them (if you're ticked off). Whatever you do, don't present your broadside to the torpedoes.
Sharp Turns. Cutting to half speed allows you to turn tighter; handy for dodging torpedoes or avoiding 'digging from clams' - hey, who put that island there?! Furthermore, agile ships can dodge incoming shells by making zig zag turns.
Smoke. Destroyers have two useful abilities - speed boost (10% more power) and smoke. Smoke allows you to lay down cover. A few tips: as you lay smoke, either turn away from enemies or cut power slightly in order to hide in it as you lay it; otherwise you can get 'ahead' of the smoke and remain visible. Smoke is handy but does advertise "destroyer over here" to everyone.
Leading Targets. Never stop moving. Clicking your mouse button once fires a single turret (ranging); clicking twice fires a broadside, and holding it "ripple" fires the gun (machine-gun hilarious on a Dresden). You always tend to need to lead targets more than you think - a 35 knot destroyer moves quite fast relative to your shots. Don't forget to aim slightly "above" the target if they are moving away and "below" if they are closing. You can fire over islands - lock a target with X, press SHIFT and often you can see over it. Your shell trajectory will usually arc over them as well.
Keep Moving. Stopping does not increase your accuracy at all. But it does increase your enemies accuracy. Corollary: Try not to present a broadside to the target, but sail towards/away from at 45d or whatever is the tightest angle that still allows you to bring your guns to bear.
Tunnel Vision = Doom. Players tend to press SHIFT and zoom in, pounding enemies without any awareness of their surroundings. They run aground, ram friendlies, are easily torpedoed and usually don't pay attention to their own ships' damage. Look at the mini map. Zoom out every few seconds.
AP or HE? You get two sorts of shells. AP can punch into the target's citadel (an armoured box approximately amidships) doing grievous internal damage while the HE starts annoying fires. Some ships are better firing one or the other. Destroyers have no citadel so you may as well fire HE at the little buggers. It's kinda situational in other circumstances so I'll leave this one for more experienced players.
Repair Wisely. You have a "repair" (R key) on a cooldown that puts out any fires/stops flooding/restarts engines. It does not recover HP, but simply stops more HP from draining. Sometimes it pays to wait a moment before repairing if you are under enemy fire; due to the cooldown it can be a pain to fix a fire, only to have your engines knocked out a second later with no way to repair them until your repair "refreshes".
Random useful information:
You need to be on the Port screen to leave a division you are in.
Alt key shows lots of detailed information on friends and foes.
What about aircraft carriers?
Bugger off. This is World of Warships, not Command and Conquer. I bet you like artillery in World of Tanks. Luckily there are no carriers, only 'proper' ships at Tiers 1-3.
Anyway, hope this helps any newbie sailors like myself - I had to learn this all the hard way. (by googling it? ;-) As usual, I play on the NA server, so if you are playing say hi in chat.