How often have you found yourself doing something you’d rather not, having agreed against your better judgment? Saying yes when you want to say no, and vice versa, causes resentment and stress.

We may feel guilty saying no to someone else. After all, it would be easier for them if we agreed to their request, and aren’t we supposed to help others? But we all need to decline a request from time to time. The sky won’t fall if you say no – it’s okay for others to adjust to your wants sometimes. Your opinions and feelings are just as important as those around you.

If you habitually can’t say no, it can be confusing to others. Your friends and co-workers may begin to take your agreement for granted, or wonder whether your agreements are genuine.

Saying no is about setting boundaries – it’s part of expressing what is you and what isn’t. And you have a great deal of control over where you set your limits.

When you begin changing your typical affirmative response, start small: get comfortable saying no in relatively low-stakes situations before taking-on bigger challenges. For example, perhaps you have a father who, because he no longer drives, asks you to do his daily errands as soon as you get off work. You find this burdensome, but dread turning down his requests because you want to help him.

For practice, you might work up to it in a less emotionally charged setting: If you usually go to lunch with a bunch of coworkers, and you’d like to make a change, you could calmly decline their invitation by telling them you’d rather sit quietly and recharge. Practice saying no to the group once or twice a week. After doing this for several weeks, you will be better prepared for making a change with your father. Once you decide to take on your father, again start small: Perhaps delay running his errands sometimes until after dinner. Then skip a day and begin to cluster the errands into a timeframe that is more convenient for you and sufficient for him.

As you start flexing your assertiveness muscles, be sure to choose your tone carefully. If you’re out of the habit of saying no when you mean it, you’ll need to learn how to express yourself without overdoing it. After all, it wasn’t their fault that you didn’t say what you meant for so long! Remember the difference between aggressive and assertive behavior: People being aggressive ignore others’ rights in meeting their own needs. People being assertive meet their needs while taking into consideration others’ needs, along with the demands of the situation.

It’s a big change – it’s not easy and you’re almost certain to make some mistakes as you learn. If you fall back into old habits of always saying yes, or find yourself being more abrupt in declining requests than you’d like, it can be helpful to practice with a trusted friend by role-playing. Visualize how you would like to feel, and what you would like to say – get very clear about what you would like to happen. Start by practicing asking for more time to decide: “I’d like to think about this for a bit and get back to you about it.”

Eventually, as you get more comfortable with determining what you would like to say and saying it, you will learn to say no directly in response to a question, rather than waiting until the situation looms larger than it is.

Getting along requires both honesty and flexibility. The goal here is choice, choosing when to say yes and when to say no, based on your overall preference, after considering your needs, the needs of others, and the likely consequences.