Start Mining at the Right Level
To find diamonds fast you need to mine at the best level. Go to Y level -59. This is the most common spot where diamonds spawn in Minecraft Download. Use the debug screen to see your Y level or press F3 if you on PC.
Use Strip Mining
Strip mining is the best method. Dig a straight tunnel 2 blocks high and 1 block wide. Then make side tunnels every 2 blocks. This helps you find more diamonds without missing any.
Bring the Right Tools
Use an iron or better pickaxe to mine diamonds. If you use wood or stone the diamonds will break and you get nothing. Bring lots of torches food and extra pickaxes so you dont run out deep underground.
Use Fortune Enchantment
If you have an enchantment table try to get the Fortune enchant. Fortune 3 gives you more diamonds per block. You can double or even triple the amount you find.
Check for Lava
Diamonds often spawn near lava pools. Be carefull and always dig around lava to find hidden diamond ores. Use a water bucket to turn lava into obsidian and stay safe.
Final Tip
Always carry a water bucket torches and enough food. Dig smart at the right level and use enchantments when you can. With a little luck you will get rich in no time.