If you do not know what fps is, it is your Frames Per Second. When you are really glitchy and your Minecraft is really slow that means your fps is low. Many people in the Minecraft community might have a bad computer or graphics card giving them a hard time to run Minecraft. There are a few ways I would like to go over to help you get the best possible fps for your Minecraft experience. I will go over Optifine, Minecraft space, and of course settings. Many people don't think changing specific setting do all that much, however, they go a long way. Some setting effect the game even if they are small.

Optifine:
Optifine is the most popular mod on he market today. A simple installation for such a amazing mod! Optifine gives you more settings to up your fps giving you a better experience. Scan through many settings to see which is the best. If you hover your mouse over the setting it will give you a description of the setting and which is the better option.

Minimizing your window:
Minimizing your window improves your fps a tad. Putting your Minecraft in full screen tends to drop your fps a bit so leave it a little smaller.

FOV:
FOV is how wide you see. Putting it lower gives higher fps because it does not have to load as much.

Hope this helped :D
Optifine: Download here