If you're a Christian, you will never be cool, and you need to accept that.
Right now, Churches worldwide are in Black Tuesday like panic-driven hysteria because Millenials (people born from the mid 1980s to the early 2000s) are leaving the church in epidemic numbers. And because of that, Churches are taking their cue from Madison Avenue and trying to give the people what they want.
Hipster churches, with t-shirt wearing new age preachers are tailoring their message to make Church easily digestible to younger people. Now there's nothing wrong with wearing T-shirts or scarves or having a faux-hawked preacher. The issue becomes the message. Christians don't blend in, we are literally the exact opposite of cool. Look at Luke 13.
"Then Jesus asked, “What is the kingdom of God like? What shall I compare it to? It is like a mustard seed, which a man took and planted in his garden. It grew and became a tree, and the birds perched in its branches.” Luke 13:18-19
You know this one, right? Something small grows into something big, just like the Kingdom of God. I get it. Hold on though, what do you know about mustard trees? The tree Jesus was describing was not an inspiring piece of flora. It was the Ryan Seacrest of trees--annoying and suddenly everywhere. It grew fast and furious and it was viewed as gross and repulsive. No one would ever, EVER, plant a mustard tree in their garden.
Bit adding further insult, Jesus is poking a finger in the eye of Jewish expectations of the kingdom of God. He's referencing Ezekiel 17.22-22 where God says,
"On the mountain height of Israel will I plant it on a high and lofty mountain will I plant it that it...may become a NOBLE CEDAR. And under it will dwell every kind of bird; in the shade of its branches bird of every sort will nest."
The cedar was the most noble of trees (yes Jews had noble trees) and Jesus replaces this noble tree with the a repulsive substitute.
Christians will be viewed as repulsive to the world. You cannot be a cool Christian.
If you think you can swoop under the radar with cool Christianity, then you're probably doing something other than following Jesus.