I'm GUAGUAMA, and I've only played League for about 6 months. I do play a lot of Xin Zhao top though, and he's the champ I have the most mastery on and enjoy the most. If you have feedback, please leave it in the comments, and I will update the guide in the future.

I started playing Xin Zhao top because I unlocked him before I had smite. Surprisingly, it can be pretty effective in the right matchups. Xin's passive gives good sustain. His W is poke/slow. His Q gives damage and provides knockup. Xin's E increases attack speed, which helps take towers and clear waves, especially with Tiamat/Titanic Hydra. Your R has a relatively low cooldown, and can be used to defend against ganks. I've also noticed that in lower elos, your E can cause your opponent to panic and try to walk away instead of fighting, which doesn't work well when paired with your Q and your W.

I know most guides recommend Phase Rush or Sorcery as one of the trees, but I prefer Precision for the attack speed and Resolve to recover from trades. Conqueror is good for longer trades, and you can use your E to engage as soon as it's ready. Press the Attack boosts damage from all your auto attacks, and is easy to proc with your E.