First of all, this build is specialized for dual lane. That's why I didn't add Bottle in build.
At early game, use Dragon Slave to harass enemy but do not waste for creep kill. After getting Bloodstone, you may now use your skills to get creeps down or attack and move faster which is caused by your passive, the Fiery Soul.
Do not waste your ultimate with health point reducing. Using it to give enemies instant dead would be nice. Good luck!