Mesmer Interupts?

I have just recently ascended to level 20 as a Mesmer and so far I am loving it. I consider myself pretty effective at PvP and I specialize in shutting down casters. One area of my profession I find myself limited however is interupts. I know the Mesmer is supposed to be one of the best professions for interupting spells, yet I have an extremely hard time landing spells such as Power Spike. I am wondering if there is a strategy to casting the interupt spells sucessfully. One of my main problems is I'm not even sure if a spell is being cast or not. Anyone have any strategies for how to time my interupts? Are there certian clues I should look for when a player is casting a spell other than the visual effects that appear over the character's head?

Mistress Juliana...

I don't know the answer to your question, but wanted to suggest maybe asking this over in the Gladiator's Arena forum, since that's a strategy discussion group. This forum seems to be populated by questions from new players, and you may find a more indepth response from ascended veterans over there.

If you are having a problem with timing interrupts, then you can use arcane conundrum or migraine to slow down the enemy's casting speed to give you more time to interrupt. To interrupt effectively you need to be familiar with pretty much all the spells out there and know which spells can or cannot be interrupted by looking at the skill icons (i.e. Reversal of Fortune is 3/4 cast time - almost impossible to interrupt without conundrum, some of the necro touch spells are classified as skills instead of spells - these cannot be interrupted, etc.)