This is my way of playing terrorblade.

---Starting items---
I usually start of with RoP to increase our already huge amount of armor thus balancing our low hp.
Tangoes + Flask and 3 branches.

---Early-Mid game---
You should try to harrass your opponent with your Q ability on lane as much as possible(if it's possible) and farm at the same time. You should buy boots and finish your RoA and then build Yasha. RIGHT AFTER(!!!) you should finish your boots and my choice is - Boots of Travel. This may sound strange , because you usually build PT/Phases on hard carries, but BoT will increase your speed with Metamorphosis AND what is CORE in my way of playing Terrorblade - will allow you to CONSTANTLY split push! YES, SPLITPUSH! Terrorblade isn't that type of hardcarry which should fight right away after he got his earlygame/core items. With the help of his Metamorphosis > W > Manta he is able to push down the whole lane in a short period of time whilst you keep the enemy team on another lane/place on the map. By splitpushing you will earn $$$ and will be able to buy Eye of Skadi. This item gives us tons of stats and hp, thus improving our illusions and pushing/fighting potential.

---Late game---
Late game is when you get your last 2 items. By this time you should have enough money for Butterfly and HoD/Satanic. At this stage it's almost impossible to lose the game. You use Metamorphosis, you make illusions, you send them to one lane, you group up with your team on another one and you push & fight at the same time in different places. Even if the enemy team is somehow able to take you down(usually enemy heroes escape with low hp after that) your illusions will finish off the enemy rax.

I will try my best on improving this guide over time. THX for your attention!