In most CP Parties nowadays people are Skillchaining and Magic Bursting off of the chain, so if you want to practice the timing and get used to doing that, a CP party is a relatively safe environment.
In order to optimize your magic bursts, you need a fast cast set and magic burst gear (which can just be regular nuking gear). The reason the fast cast is important is because you have a full 10 seconds from when the second weapon skill lands and triggers the skillchain. Ideally you can get off two strong spells in this 10 second window, most commonly -ja and then a tier 6.
If there are two melee in the situation that it's likely that they will be doing a skillchain that results in either Light or Dark.
On light you can burst: Wind, Fire, Thunder, or Light
On dark you can burst: Stone, Water, Ice, or Dark
It's very common now that scholars will be the ones creating a skillchain using their strategem Immanence.