God wants us—every one of us—to have a strong faith in Him. He wants us to have a faith that doesn't waver or come and go, and one that will be strong enough to see us through life's trials and temptations. Have you asked Him for this kind of faith?
Faith, however, doesn't just happen—any more than a strong body just happens. To have a strong body, you need to eat well, and you need to avoid things that could harm you or make you sick. You also need to exercise and take care of your body. The same is true with our souls. We need to avoid things that will harm us or make us spiritually sick, and we need to exercise our faith and put it into action. Most of all, we need to "eat" the spiritual "food" God has provided for us.
What is the "food" God has given us to strengthen our faith? First, He has given us His Word, the Bible. In it He tells us what He has done for us, and how we are to live in return. Then God has given us the privilege of prayer, so we can come into His presence and share our deepest concerns with Him. He also has given us other believers, who can encourage and guide us.
The Bible says, "Physical training is of some value, but godliness has value for all things, holding promise for both the present life and the life to come" (1 Timothy 4:8). Make sure you have committed your life to Christ, and then make use of the spiritual "food" God has given you to grow in your faith.