(figuratively) a drop in the ocean, a drop in the bucket

(figuratively) to live under a rock

(informal, figuratively) to have one's head in the clouds

(figuratively) to fall through

in great detail, in minute detail, in every detail, down to the very last detail, down to the smallest detail, minutely

(transitive, figuratively) to have an innate ability in something, to be naturally gifted for something

(informal, slang) to not be feeling good, to have a thick head

(informal) to rush in, to barge in there, to go scorched earth, to go straight into it

(figuratively) to trim, to remove what's superfluous

in the case of, when it comes to, as for, regarding, concerning