If you ever wanted to find diamonds it will help if you mined in a diagonal position so you can go lower into the ground slowly with less chance of running into lava. You should usually mine at a certain level for a little. At some point you might a break a block and water comes running out. You may patch it up but don't! Not yet anyway. Go to the source and you will usually find multiple diamond ore.

Patches, Another way to find tons of ore is to look for patches. If you find a piece of ore mine around or look up, most of the time you will find 1-3 more ore if you do this. This is really useful if you need to find a certain amount of ore to do something. You can obtain a lot more ore if you do use this method. I will try to update this more so, Thank You