Annie is a great mid player, but is always an amazing support.

This is a basic guide detailing some things to do when playing support Annie.

Annie's Passive: Pyromania
Is an amazing passive.
On every fourth ability cast, Annie's next offensive ability will Stun icon stun all enemies it damages for 1.25 / 1.5 / 1.75 seconds.

Q: Disintegrate
RANGE: 625 COST: 60 / 65 / 70 / 75 / 80 MANA COOLDOWN: 4
Disintegrate
ACTIVE: Annie hurls a fireball at a target enemy unit, dealing magic damage on-hit.
MAGIC DAMAGE: 80 / 115 / 150 / 185 / 220 (+ 80% AP)
If Disintegrate kills the target, it refunds its mana cost and its cooldown is halved.

W: Incinerate
RANGE: 625 COST: 70 / 80 / 90 / 100 / 110 MANA COOLDOWN: 8
Incinerate
ACTIVE: Annie scorches all enemies in a 50° conic area in front of her with fire, dealing magic damage.
MAGIC DAMAGE: 70 / 115 / 160 / 205 / 250 (+ 85% AP)

E: Molten Shield
COST: 20 MANA COOLDOWN: 10
Molten Shield
ACTIVE: Annie grants herself a shield of fire for 5 seconds that grants bonus armor and magic resistance as well as dealing magic damage to enemies each time they attack the shield.
ARMOR & MAGIC RESIST: 10 / 20 / 30 / 40 / 50
MAGIC DAMAGE: 20 / 30 / 40 / 50 / 60 (+ 20% AP)
If Tibbers is active when Molten Shield is used he will gain the shield, while also gaining a flat 300 movement speed bonus that decays over 0.75 seconds.

R: SUMMON TIBBERS!
ANGE: 600 COST: 100 MANA COOLDOWN: 120 / 100 / 80
Summon- Tibbers
ACTIVE: Annie summons Tibbers to the target location in a burst of flame, dealing magic damage to enemies within 290-range. Tibbers remains on the field as a controllable minion for up to 45 seconds.
MAGIC DAMAGE: 175 / 300 / 425 (+ 80% AP)
Tibbers deals magical damage with his attacks, and is also surrounded by a flaming aura that deals magic damage every second to enemies within 200-range of himself.
MAGIC DAMAGE PER SECOND: 20 / 30 / 40 (+ 20% AP)

Skill your 'W' first so you can have a level 1 stun if need be.

Once level 2, if you still have your 'Passive' up, use your 'Q' on their ADC [or whichever is closest] to stun, then use your 'W' to damage them some more. Walk back to safety. Keep harassing them and kiting their attack with Annie's long range.

When level 3, skill your 'E' shield, so you can activate your passive faster, using the low mana cost ability [so you are not wasting your mana, or using your 'Q' on minions to take your ADC's gold]

Once Level 6, if you see an opportunity, have stun up and Tibbers [trying to get both of them], 'Q' the ADC and when they start running, use exhaust on them so they cannot run as easily. If your ADC sees this, they probably can get a kill from this [especially if it is ADCs like Vayne, Jinx or Ashe]

From here on out, Annie practically does the same. Warding the general areas, using RED TRINKET to check for wards and being a nice initiator in team fights.

If you have your stun up, you can do a lot in team fights with Tibbers. If you know your team might be fighting, try and keep your PASSIVE up [by using shield and incinerate to activate your PASSIVE]. If you and your team see an opening for a team-fight. Tibber with Stun as many people as you can [or their strongest champion].

Q+W: Is a nice way to harass your enemy ADC in lane.
To make it super effective, make sure Annie's Passive is up before attacking

IN TEAM FIGHTS:
[With your Passive] R+E+W.
Summons Tibbers, then cast your AOE affect on the stunned enemy team. Then use your Molten Shield as it grants Tibbers the shield as well.