Pick two thresholds:
- Maximum amount of time you're willing to allocate to a specific task. (Example: 1h. FYI, David Allen of GTD fame recommends 5min for very senior execs.) Try to delegate anything above that number.
- Amount of time you'll take you to get it done vs amount of time it'll take one of your directs or skips to get something done. (Example: a task that you could do in 1h will require 10 man-hours if done downstream.) Pick a number and try to delegate anything that requires less downstream effort.
When it comes to delegating, remember: back when you were an engineer or a new manager, you sucked at what your boss was delegating to you, but you managed to produce something that was good enough and you became better at it with time. Your directs and your skips will learn too.
Also:
- Learn how to hire. If you're managing managers you absolutely want dependable directs who you trust will get done whatever stuff you delegate to them. And frankly, the same holds when you're managing engineers. (As an aside, a common mistake in early stage startups is to let the founders or HR hire for you; you're going to be the one managing whoever gets hired, so push back if you've no say over who gets hired.)
- Put a weekly 30min 1:1 with all of your directs in your calendar if you're not doing so already. It'll save you lots of interruptions because your directs will know they've some time allocated for less urgent stuff, and it'll allow you to surface incoming problems before they blow up in your face.
- Ax the time you spend on email to free up your calendar. Pick 2 or 3 time slots during your day. (Example: early morning upon arriving, before or after lunch, and before leaving.) Block those slots in your calendar. Only do email during those time slots. (Close your Email client and turn off notifications. If anything's actually urgent, your phone will ring.) Also, create filters to surface what's important and what's not. (Anything cc'd to you or not sent to your email directly probably isn't high priority; stuff sent by your boss or by your directs probably is.)
- Block a few hours in your calendar to actually get your own work done. Part of your job arguably is to be available, but if your calendar is wide open it invites your coworkers to swamp you with meetings. And be picky with meetings. Unless it's coming from your boss, refuse to join meetings that don't have a clear agenda. (Send one of your directs instead.)
- Build good-will and political capital in your organization. At senior levels, I'll scratch your back if you scratch mine tends to count a lot. So don't hesitate to spend a half hour every so often with other managers that deal with stuff your teams have interaction with to catch up. (There's no point in building a new product if the heads of marketing and sales don't both think there's a market.) Don't confuse this with schmoozing, else your weekly or fortnightly meeting will be first to get binned when calendar time is scarce. But work on those relationships.