Powers Activate - Lower the activation energy to make it easier to do
One of the hardest things to do is get started, frequently many habits, activities and actions are easy to complete if you start them. If you can get on the tread mill for 30 seconds, you likely can go for 20 minutes, but it can be very hard to get on the treadmill.
Similar issues can be found in writing, doing homework, or any task that mentally seems more onerous than it is.
One of the best ways to get around this is making starting as easy as possible or as James Clear puts it well reduce the activation energy (usually by introducing a catalyst that makes it easier for you to start things).
Other things that make it easier - laying out your workout clothes the night before. Setting up a small gym right next to your bedroom so you don't have to go far.
Setting up your workspace to minimize distractions. All these things make it easier to start the habit and for many that is half the battle.