To trust God, or to have faith in God, means that you have gotten to know Him so well, that you believe what He says. For example, Jesus told us in John 14 that He was going away to heaven to prepare places for us, and then He would return to receive us to Himself, so that where He is (heaven), we would also be. Do you believe that? Well, I suppose if you have been in a close personal relationship with Him for a while, as I have, you believe Him 100%, and you cannot wait to get there. But if you do not have a relationship with Him, then you would wonder about it, maybe doubt that it is true, or just totally disbelieve it. In order to trust God, you have to know Him. And you only get to know Him, by spending time every day with Him, talking to Him (prayer), and allowing Him to talk to you (reading His Word, the Bible). It cannot happen in a few minutes, so quality time, and enough time to really open your heart to Him, is important. Without that, forget it, you will never trust Him.

As far as your schoolwork is concerned, no-one gets good grades without work. God cannot help you unless you have put in the hours of study, but if you have, He says, trust Me to give you a good memory, to help you be calm under stress, to make the correct decisions about answers. If God is number One in your life, He is there to lead and guide all the way, not just in schoolwork, and if we trust Him, He shows us the way to eternal life.

Proverbs 3     ⁵ Trust in the Lord with all your heart, and lean not on your own under-standing; ⁶ in all your ways acknowledge Him, and He shall direct your paths.

I hope that this makes sense. God bless!