I've written quite a bit about focus, because I think it is so important to achieving long-term success. Sometimes, you just have to pick a path and commit to it for a time, without getting tempted onto the little rabbit trails that exist to distract you.
But what happens when you have a manager or a boss who isn't as good at focusing? When the person who writes your performance evaluation or signs your paycheck likes to pepper you with a barrage of suggestions and ideas and fabulous new ways to do business? When you know you should say no to them, but you don't feel like you can?
The solution here is to learn some really useful business jiu-jitsu. Instead of chasing all those rabbit trails and fabulous ideas (some of which might actually be fabulous!), you need to develop a respectful, sincere way of parking them in a safe place until you are ready to tackle them. Here's a surefire process to make sure your boss knows they are heard and their ideas aren't going to waste, AND you can focus on your agreed-upon priorities.
Acknowledge the idea. Obviously, it is important to not leave someone feeling like they are shouting into the void. That typically just results in an ideas person doing an end-around and going to the next available person, even if that person is your direct report and that conversation is outside the chain of command.
Remind them of your priorities. Saying, calmly, "That's an awesome idea, but right now, the team is working on X and Y and Z, as we decided, so we'd have to drop one of those projects in order to work on this." often stops the idea train in its tracks, because X and Y and Z are probably more fully-fleshed-out ideas AND more significant priorities.
Develop a legitimate parking lot for these ideas. This does not mean tossing them in the trash, or putting them in a file somewhere where no one will ever see them again. This means having a file or a spreadsheet or an ideas board where ideas get parked until the team has capacity again, at which point you and the ideas person and anyone else who needs to get involved can look at the list and see what you, collectively, want to tackle next.
On my sales teams, we have a policy of never working more than three campaigns at a time. If someone suggests a new campaign when we are already at capacity, we put it on a spreadsheet we literally call "Ideas of the Day." My campaign coordinator does research on each idea in the order we think most likely to succeed, and we have a long, ongoing list of potential future campaigns coupled with an understanding of how many opportunities those campaigns represent. When the team gets close to finishing one of our campaigns, we simply go to the list, look at our options, and pick what's up next. It's an efficient way of dealing with those 3 a.m. flashes of brilliance without getting distracted from our process.