Fire situational rotation help

[Phloobz]

Hey guys, 2 questions:
1. Meteor usage: Should it be paired with combustion, or is it not worth the GCD? Outside of that, it should always be used on CD & paired with RoP right?
2. Trash - In dungeons, I usually top DPS on bosses, but struggle with trash. I'm not sure what I'm doing wrong, can someone explain the way they approach trash. In general I understand the rotation, but I find I either take to long to ramp up e.g. casting fireball in search of a crit to begin chaining, or the mob dies before say living bomb/meteor can be effective. I want to be able to run high M+, so how can I improve/maximise my dps on trash? Should I open with a double fireblast to get the crit chain rolling ASAP?
Thanks in advance!

[Sosaria]

1. Meteor, when used, has a travel time... if you're entering combustion and Meteor is off CD, you use Meteor -> Combusion -> burn rotation

2. Due to the ramp up time for Fire, you're never going to ever catch up in dps on mobs packs that die too quickly. Your effectiveness will become more apparent in higher Mythic+ keys.

Note however, that Frost and Arcane will still out dps in almost all scenarios right now (ST and AOE), and Frost especially as they bring slow utility.