just started flowering a few days ago. when should I trim off the small lower branches and large leaves that block light? what's the best way to go about it? thanks

Don't touch the large leaves mate, no matter what. Thats where the plant gets its energy from. Remove those, and you will slow the growth and end up with much smaller buds come harvest time

I would give it a week or so, until you can see the way its going to grow out, and then remove everything from the bottom up thats not every going to turn into a decent sized bud. I usually remove the lower 3 or 4 internodes, but it all depends on how the plant is looking, how many colas are forming ect.

ok. well my plants are very bushy and the lower levels are not getting proper light and they actually dont even have room to grow up anymore. there's some tiny branches that are trying to grow up, but i heard that cutting the low level brances off has a good effect... something about creating an "air pocket" or some shit like that so when should i do it? another 2 weeks maybe?