Because I master all things by The Messiah who empowers me. ~ Philippians 4:13 ABPE
As you begin to believe and declare you can do all things, Yahweh will give you opportunities for your Faith to be tested. And while those tests are occurring, the enemy's going to pop up with temptations to get you off your Kingdom Path. Here's how you overcome:
Remain focused on what you want to accomplish. For example, let's say The Father called you to write a book, you said yes and declared you can write one. He may test your Faith by giving you a download at a time when you weren't prepared but He wants to see if you'll be diligent to pray into the Revelation, take notes and then sit down to write the chapter as soon as you have free time. The enemy may attempt to put the flu on you to get you to agree with his plans instead of God's and if you agree with them, you'll delay. Or more commonly, they may plant seeds of fear and doubt about your ability to write or your audience's desire to read.
Keep The Word of God in front of your eyes and coming out of your mouth. Whatever gets your attention is where your life will go. Whatever you believe is what you speak. If your attention is on The Word, your life will follow suit. Same with your words - if you're speaking what God speaks, Faith is being built.
Take action according to your goal. You can say yes all day, tonight and tomorrow, but if you don't follow up those words with corresponding action, you won't be able to manifest The Kingdom in your life.
Say aloud 3 times today:
When I believe God's Word in my spirit and say it with my own words, I can master everything in this natural, physical realm and overcome the enemy.