
There are several conditions that could cause a world to either not have a Stronghold or have Eyes of Ender that point in the wrong direction. Should only take 1-4 extra throws and will get you exactly where you need to be. This is probably the quickest if you have a couple extra Eyes of Ender you can spare to lose.

If it flies behind you, walk to where it lands, throw and repeat until it flies into the ground. Repeat until it flies into the ground or until if flies behind you.

Repeat the whole process with your first throw being in the general area of the initial estimated location, then walk off to the side (not in the direction the Eye floats) about 50 blocks or so and perform your 2nd throw there.There are a few solutions: (click here to expand them) If it flies up and away from you then it generally means the first, or both of your angles are slightly off due to input error or the way Minecraft estimates the stronghold location prior to it actually beinggenerated. If it flies towards the ground and hovers you're in the right spot and can start digging down and looking for the stronghold. Before you dig down, try climbing on top of a tree or building up about 20 blocks above the ground and throwing another Eye of Ender. Depending on several factors this estimation might still be off by up to 100 blocks or so. Now go to the estimated End Portal Location.
