I think brown tips is usually from a little bit of nutrient burn. If you are using pre-fertilized soil this can happen, or if you use a little too much ferts. Try plain water for your watering and see if it quits happening.

Are you in flower or in veg? The leaves provide sugar to your plant. If there is a leaf blocking the light to a bud you may want to either tuck it out of the way or if the leaf is yellow then cut it off. But a green leaf is working hard pumping sugar into the plant. If you are in veg, then a new branch blocked by a leaf isn't the leader and it won't grow much anyway unless you trim the plant in such a way as to make it the new leader.