Choose your friends wisely. Do not allow your choice of friends to be a stumbling block to others, or even worse, compromise your faith.
Rejoice in being hated for your faith. For they will hate you like they hated Christ two millenniums before. If you try to make the world love you, you are not being like Christ, plain and simple.
"Be ye not unequally yoked together with unbelievers: for what fellowship hath righteousness with unrighteousness? And what communion hath light with darkness?" (2 Corinthians 6:14)
Paul is telling us that believers and unbelievers have no communion together. Believers and unbelievers have two totally different outlooks on life. Christ vs Self. Pleasing yourself (in ungodly things) is antithetical to what Christ wants us to do. We are to please Christ by obeying Him and keeping in communion with Him!
"And what concord hath Christ with Belial? Or what part hath he that believeth with an infidel?" (v. 15)
This is obviously a literary usage of hyperbole, but it is true. Christ and Satan are completely opposite, so comparing yourself to an unbeliever is the same way. In a crazy fashion, you could say that you're an alien amongst 'normal' people. There is a verse about how we're 'peculiar' people, but I forget the reference. Sorry!
"And what agreement hath the temple of God with idols? For ye are the temple of the living God; as God hath said, I will dwell in them, and walk in them; and I will be their God, and they shall be my people." (v. 16)
We are temples of the Most High God. Imagine bringing an offering to the LORD, and it is strictly against His rules. That is what it is like to be yoked with unbelievers. We are to be examples of Christ, not of this world.
"Wherefore come out from among them, and be ye separate, saith the Lord, and touch not the unclean thing; and I will receive you." (v. 17)
Be different from them. If they adapt a certain trend, I'd suggest you resist it. Be not like them. Be an example of Christ to them. Having friends is great, but when you become less like Christ around them, reconsider being around them.
"And will be a Father unto you, and ye shall be my sons and daughters, saith the Lord Almighty." (v. 18)
You are a daughter/son of Christ. Just act like it. Be like it. Ask God to change your whole essence to being a child of Christ.
Last but not least, the verse right after the end of 2 Cor. 6, the first verse of Chapter 7, says this:
"Having therefore these promises, dearly beloved, let us cleanse ourselves from all filthiness of the flesh and spirit, perfecting holiness in the fear of God."
Fear doesn't mean to be afraid here. This type of 'fear' is reverence for the LORD. We are to repent of our sins and run from them, in the reverence of our LORD, who is Christ Jesus. We do this out of love for our perfect Creator.
"If ye were of the world, the world would love his own, but I have chosen you out of the world, therefore the world hateth you." (John 15:19)
Christ chose us to be different. Christ changed us permanently, and we are to stick out like a sore thumb in this rotten society. We are to be a light upon a hill.
"For ye were sometimes darkness, but now are ye light in the Lord: walk as children of light: (For the fruit of the Spirit is in all goodness and righteousness, and truth;) Proving what is acceptable unto the Lord. And have no fellowship with the unfruitful works of darkness, but rather reprove them." (Ephesians 5:8-11)
Be not like them who are in darkness, for they fall to their own death in their sins. For all apostasies, rebuke them. Don't be afraid to expose them. Expose their lies so they can be brought back to the truth.
"Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity with God? Whosoever therefore will be a friend of the world is the enemy of God." (James 4:4)
The Bible says, numerous times, that God and the world are at the opposite ends of the spectrum. Pick your side. Either you turn your back to the world and follow God, or you die in your sins loving the things of the world. There is no excuse to be lukewarm. If you're lukewarm, you're a lover of the world.
"Love not the world, neither the things that are in the world. If any man love this world, the love of the Father is not in him. For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world. And the world passeth away, and the lust thereof: but he that doeth the will of God abideth forever." (1 John 2:15-17)
This passage from 1 John tells us to refrain from worldly things. We are not to become materially rich and lose our soul.
"For what is a man profited, if he shall gain the whole world, and lose his own soul? Or what shall a man give in exchange for his soul?" (Matthew 16:26)
Maybe you're thinking of the TobyMac song. I'd suggest you stay away from the world. Be lowly in the eyes of the world, so you'll be obedient to our Father in Heaven.
Last but not least, I want to say that everything of this world is temporal. All the money you have, the cars you own, the anime you watch, the games you play, even the life you have on Earth… It's all temporal.
Build treasures in Heaven. Read your Bible. Ask God for wisdom. Be not conformed to this world, because it is wickedness in the Lord's eyes, and is also just temporary. Don't worry. You'll meet God after you die, if you have repented of your sins and have come to know Christ.
Don't waste your time on stupid things either. I have wasted my time, honestly, on reading novels, playing games, etc. It's all empty though. It's fun for the time, but it is just useless in the big scope of things. It'll all pass away.
Trust in Jesus.
Addendum: Dangers of Tolerance
I'm not done yet. The first part is chiefly a personal application of those scriptures. Yet, in my humble opinion, it also pertains to the Church.
One time, our church was doing a Bible study based on the book 'The Circle Maker' by Mark Batterson. Mom gave me the book so I could read it. She always does that, because she trusts me to compare it to the Bible. I do that out of love for God.
Well, it turned out that the book was riddled with heresy. A few Churchgoers threatened to leave the church because of that, and I don't blame them. Many still did the course. (If you're curious about it, look up the heresy about Honi the Circle Maker and the book itself.)
It goes to show you how little discernment there was, even in this relatively conservative Church. I'd still go, because it's 95% solid doctrine there.
You cannot allow your Church to accept things that will bring questionable doctrine into the flock of God. Don't be tolerant of theological error. Hate it. Detest heresy. God hates it too, because it's disrespectful to Him.
Even worse, is when people begin to create movements that proclaim that all religions worship the same God. That is outright heresy according to John 14:6.
"Jesus saith unto him, I am the way, the truth, and the life; no man cometh unto the Father, but by me."
The Bible is obvious in stating that Christianity is the only true faith. All other faiths are wander-some and lead nowhere except fruitless destruction. In merging religions, people essentially create an idol that represents all religions! It isn't God who is of all religions. God is the God of our faith, not theirs. Our faith is true. Our faith will stand the test of time. Our faith has been proven countless times. Their faith shall see the end when Christ comes to cast 'em into hell.