How do I get my child to do X is too simple, unilateral, and not relationship based. It lacks depth and understanding. Parenting is not so simple, and neither are children.
If you are bumping up against resistance on this, some of these questions might reframe the issue for you.
Is what I’m asking of my child reasonable?
How can I set up the environment so that X is more likely? (Or less likely depending upon what X is)
How can I explain the importance of this so my child will understand?
How can I work with my child in a way that respects his/her needs and autonomy?
How can I talk with my child beforehand or at a neutral time so that we can increase chances of success?
Are there other ways that will be more enjoyable or a win/win for all involved?
What can I do in order to help my child with X?
How can I best react in the moment, when my child has a hard time doing X, so that we maintain a positive relationship?
How can I best react in the moment, when my child has a hard time doing X, so that I don’t create negative associations around X… and, in turn, make X even less likely to happen. (This is the shooting yourself in the foot parenting move. Accomplished many-a-times by yours truly.)
How can I best react in the moment, when my child has a hard time doing X, so that I help build comfort, confidence, skills and positive feelings around X?
Why really is my child resisting/not enjoying/having a hard time with X?
Does my child really want to/need to do X?
And most importantly : How can I strengthen my relationship with my child so that my reasonable requests are more often respected?
I know this might seem like a bit much, a bit too considerate even. What this really is though, is skillful parenting/skillful management. Yes, it might take longer to learn and a bit longer to employ, but the results will speak for themselves…happier children and more cooperation. In time, this approach will save you time and will cut-down on the power struggles considerably.