When you think of advocating for yourself in the workplace, you probably imagine asking for a promotion.

Part of self-advocacy, though, is learning how to say "no" to tasks you don't have the bandwidth for. This can help you dedicate more time to projects that you do find stimulating and keep you from burning out — something 44%, of workers report feeling, according to a 2024 survey by the Society for Human Resource Management.

In her new book "Smart, Not Loud," Jessica Chen outlines how you can push back against accepting more work, even if you're uncomfortable saying "no."

Chen, the CEO of communications training agency SoulCast, writes that she was raised in a culture where it was "easier to acquiesce and accept projects" because you wanted to look like a team player.

But, ultimately, that is not sustainable for living a healthy, balanced life.

"In the process of always saying yes, we sacrifice our time and take on work that does not really help us," she writes.

In her book, she offers up a formula that can help you turn down work in a way that doesn't ruin your workplace relationships.

Tone, explain, follow

When you're approached with a project or task you want to reject, employ the TEF model:

1. Tone: Keep your tone "neutral and matter-of-fact," Chen writes. This communicates certainty so others don't think your boundaries are negotiable.

2. Explain: Share why you're saying no so you don't appear dismissive or complacent. For example, if you have looming, more pressing deadlines, let your manager or colleague know.

3. Follow: Suggest other ways the task can get done. This shows that you care it's completed. "We can suggest alternative times for others to check in when we have more free time, or provide other avenues for them to explore," Chen writes.

Brandon Smith, known as The Workplace Therapist, suggests a similar strategy to Chen for setting boundaries at work.

When you're telling a co-worker or manager that you can't take on a to-do, your reply should be "20% 'no' and 80% alternative solution," Smith told CNBC Make It.

It also helps to abandon the thought that you are the only person in the world who can help.

"While we think that they think we are the savior, all they want is someone to do this thing," Smith says. 

If the task is really that important or urgent, they will find someone else to do it.

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