If the Wi-Fi blocks the game download:
Watch your Eco counter. If you spend all your money on defense and nothing on sending bloons, your opponent will have double your income by Round 20, allowing them to overwhelm you with expensive rushes. Balance defense with sending "pink bloons" to raise your eco to at least 600-800 by the mid-game. bloons td battles unblocked
If you are looking for a guide on how to play unblocked (typically meaning you want to play it on a school or work network that restricts gaming sites), you have a few options depending on your situation. If the Wi-Fi blocks the game download: Watch