Dryads and Mountain Giants
This is an under-used strategy; it's mostly the fact that both Dryads and Mountain Giants are not affected by AOE spells such as Blizzard, Rain of Fire, and Bladestorm. Also, the Dryads slow the enemy while your tanks,(the Mountain Giants) get close enough to taunt the enemy and make them attack. But try to get 3-4 Ancients of Lore. That should make for a quick army. Don't get caught teching as a Night Elf, as they are weak against rushes for some reason. I've never really found out why.
Chimaeras and Hippogryphs
This is a very common strategy, although it is weak against tanks. Considering the fact that the Chimaeras are the highest-tech unit, along with Bears, you should have some sort of a defence while teching to the Chimaeras. Since the Hippogryphs are already going to be made and they are only 2nd tier, try getting some Archers and Hippogryphs then putting the Archers on the Hippogryphs for Hippogryph Riders. You can research the ability in the Ancient of the Wind. But if you spot mass tanks, make sure you take the Archers off when they come a little to close for comfort. <Ed. note: The archers are attached with crazy glue, so they cannot be removed.>
Dryads and Faerie Dragons
This is very effectively the Night Elves' Anti Caster. The Dryads are immune to magic and also have Abolish Magic to take away any negative buffs from allies and positive buffs from enemies which makes Priests useless. <Ed. note: Priests are hardly useless, as they have auto-heal. Also, a great counter against that annoying Possession the Undead uses. The plan mostly used with these is the Faerie Dragons go to the Casters (almost always found in the back of the group)than use Mana Flare over the Casters. This strategy only works well in non-solo games. But, if you are solo and your opponent has massed Casters. Just bring along a few Bears and maybe a Mountain Giant to take all the punishment.
This is a very fun strategy that only works early in the game against Undead. Just harass with a Hero and a few Archers. Send the archers behind the gold mine and press the hide button. Run your hero away when the Archers are hiding behind the gold mine.(If you don't do this at night you're screwed) Just unhide and damage an Acolyte. But, make sure it's very quick and the player is busy creeping. So they won't know what happened. Then, just keep it up until about 4:00am. Then, run your Archers away before they come back. By then, you should be almost done changing Tree of Life into a Tree of Ages. Finally, start what ever unit production you want. This also works with Huntresses.
The best hero for harassing the unsuspecting enemy would probably be the Warden. She can hide, Blink, Bladestorm, and Shadow Strike. If you use her to harass, then learn your first move as Fan of Blades. Make sure you set off to your enemy's base at around 9:00pm or 21:00. A good idea is to get a potion of invisibility. Use the potion then get to the workers. If its human or orc, use Fan of Blades on the miners. If it's Night Elf, just attack the ones on the trees not using any spells. If it's Undead make sure to watch out for the ghouls and attack the miners. If you encounter any trouble such as a hero. Press the hide button, if you've gained a level, use it on blink. When you're hidden, blink away and then run for your life! If you see a tower near the target workers don't even try this.