>>597284
>1. Why try to be the best christian you can all your life if you can get into Heaven with minimal effort?
Out of love towards God. There logically must be some absolute bare minimum of effort with which one can attain Heaven, but I doubt anyone who first-hand realises who God is can really remain only at this bare minimum.
>2. Why do some Christians view magic as satanic when they believe all the "tricks" (turning water into wine, walking on water,etc.) that Jesus once did?
Magic, as a kind of sin, is not just doing things naturally impossible to man - as you pointed out, Jesus did these, as did many saints after him - what makes it magic specifically is doing it with aid of any powers other than Divine; since this can only be seriously done by recourse to the demonic, it's obviously sinful.
>3. What makes you believe in God?
Faith, understood as belief in God's revelation solely due to trust in the One revealing, is a direct and supernatural gift. It's not, and even in principle cannot be, based on any logical or empirical argument. You can only pray for it, and you can be certain that if you genuinely strive to believe and persevere in prayer, God will eventually answer.
That said, the above doesn't mean that existence of God is unprovable and can only be assented to by supernatural intervention; that is true of faith, but God's nature and attributes can be deduced through reason alone too. If you are interested in this, I advise you to read a simple introduction to Scholasticism; Feser's Aquinas is a common recommendation, and for a good reason. Kerr's Aquinas's Way to God is a great book too, discussing a simple and solid, but relatively unknown, proof from Aquinas' De ente et essentia, although you should read it after you know some basics already.