Despite the changes due for the minigames it can be quite worthwhile to check out the current CTF, as you can make money very quickly. In addition, it is one of the only games where hacks do not significantly affect the outcome. Any hacker can easily be beaten in this by avoiding them, focusing on the objective instead.
"All can see the tactics by which I conquer, but what none can see is the underlying strategy from which victory evolves."-Sun Tzu, author of Art of War.

Mining Strategy

This strategy takes advantage of the diamonds that reside beneath each base. To do this at both maps, descend the staircase into the mine, and you will find a chest in the general area of the middle block. Contents depend on the map you are playing.
Mountains: 1 Enchanted Golden Apple, 1 Iron Pickaxe, 2 Iron Ingots, 1 Iron Shovel
Islands: 1. Iron Pickaxe, 1 Golden Shovel, 2 Iron Ingots

If multiple people have gone mining on your team, you can make your own iron pickaxe by the standard method of mining ore and smelting.
The goal of this strategy is to mine 26 diamonds, at which you can make a full set of diamond armor and a sword.

In the mines, there are many dangers. Cobwebs are placed sporadically, and limit combat from both the monsters that spawn and enemy players. There are tunnels that connect the four mines beneath each base, which is where you will mine. In the middle of each tunnel, there is another chest, which contain:
32 Arrows
1 Potion of Speed
2 Diamonds
Once you have your diamonds, return to the surface and harvest 2 logs. Make a crafting table out of one, and sticks of the other. Craft your armory, and descend into battle!

PvP Pro

This strategy is for those that just love clobbering people. The cornerstone of this strategy is the 2 points per kill. As soon as the game starts, rush as fast as you can to the Healing Base located at the center of the map. After this location is secure, it will provide your entire team with instant health and hunger restoration every fifteen seconds. (Usually right after you die.) Now the next step, begin the hunt! If you prefer fighting with a sword/axe, skip right over this next step.

If you are a master marksman, you can retrieve a bow and a stack of arrows, as well as some chain-mail armor from chests. The location of these chests depends on the map. They can be found in colored hot air balloons near the Healing Base at the Islands map, and in wooden towers in between bases near the edge at Mountains.

Now the time to fight has come! Take note of which teams have the most members, and focus on larger teams first. You can see if someone is mining from the surface by looking closely for colored name tags. Generally, if you kill a miner who has amassed diamonds (for you now, how nice of them!), they will ragequit. If you kill a miner who does not have enough diamonds for a complete set, prioritize the pieces in this order: sword, leggings, helmet, boots, chest plate. Chest plate last because you start with a leather tunic, so you will gain the maximum armor points for your diamond with this order.
This is super fun if no enemy is near as good at PvP as you, as they will grow frustrated of constantly losing. However, do not make it absolutely impossible for someone to leave their spawn because you kill them immiedietly.

Cap, Cap, Cap!

This strategy revolves around the principal of you get fifteen points per enemy flag capture. (You receive only five points for reclaiming your own flag.) As soon as the game begins, rush for enemy flags, and take all 3 flags as soon as possible. Take the Healing Base if necessary. Always keep an eye on the chat to see if an enemy has "capped" another flag after you. This means you can return to that flag and cap it again!

Common Mistakes

Defending your flag/making a base

Easily the most common tactical error, this rarely affects the results of the game positively for your team. By remaining at your flag, you are not acquiring points for your team. The same principle applies to creating a base.

Spawn Camping

Call it a glitch or a safeguard, the fact remains you cannot damage an opponent directly on their spawn. One problem for you: they can still damage you. Therefore, I would advise keeping your distance when near an enemy team's spawn.

Afterthoughts

Each strategy has its advantages. Mining allows you to basically become invincible, but gives you a slow start to the game. Clobbering the enemy is fun, and keeps them from amassing resources, but is not very rewarding in points. Capping is the simplest way to win at the start, but it stagnates once you have claimed all the flags.

One of the most important things to consider, all three strategies can be carried out to greater effectiveness if you have teamwork! Personally, I have won a game of me vs 3 on every other team because none of them could work together. Instead, they counteracted each others' work. There is no team chat, currently, so the best way to communicate with any random member of your team is through /msg. However, for those you deal with frequently, you may have a set strategy, or communicate through other means (Skype, Teamspeak, etc.). One way you can ensure teamwork is to form bonds with frequent teammates/enemies. Everyone loves playing with people they like!

You will never contribute to your team's overall performance by complaining about how "bad" they are. "No king is saved by the size of his army; no great warrior is saved by his strength."-Psalms 33:16

Good luck, and have fun!