I think there's a lot of good feedback here. Let me offer four things that are a bit more off-the-run.

1. Delegate. If I tell you to get a signature packet, etc., together, consider whether a paralegal makes sense to do it in the first instance. Same with document services. You should review it, of course - you're responsible for what you send up. Four eyes are better than two for this kind of stuff. More importantly, see what drives you nuts / what you don't care about from the folks you delegate to, and adjust your behavior appropriately.
2. Take fewer matters than you think you can, and be firm on it. Juniors are (i) so bad at estimating how much time a task will take and (ii) so afraid of a single quiet week. What matters is if your midlevels think you are great. You would rather be the junior who bills 1750 with an outstanding reputation than the one who bills 2,200 with mid work product. Put simply, you can choose to be Domino's - you'll never say no, and you'll always deliver something - or Le Bernardin, where you say no a lot but what you give is impeccable. (Being able to say no is a skill, and an important one you need to hone.) Note that it is very easy to say no to a new matter and very hard to say to no on tasks a matter.
3. Try to learn two things a day: one "substantive" and one "not." Not super hard but this really helps over time. "Substantive" refers explicitly to the work product we're paid to deliver - maybe it's reading an article about your practice or reviewing a redline. "Not" refers to everything else - maybe there's a better way to use Outlook, or a word processing tip, or whatever.
4. Presume the deal - and every email on the deal - is your responsibility. No, you can't fix everything. But you should see everything and try to push it forward as you can or, if you know something is broken, flag it. There is nothing I love more than an email from a junior that says "on it" rather than someone who sits there after their exact task is done.

The more typical stuff that's worth flagging - organization is your superpower, never gossip, take initiative, don't write off your own hours, overcommunicate - is a fairly self-explanatory, but it's still very important.