How To Sightread Music Effectively

The key to sightreading music is being able to recognize notes quickly. This skill can help when you play piano.
The goal of sightreading is not to play the song at the correct speed. Instead, the goal is to play the song correctly. Playing notes the first time correctly makes it easier than trying to fixed a wrong note you've been playing incorrectly.
When you begin sightreading, you should start with simple songs. Easy ways to do that is to try out songs from a beginners book or print some sheet music online. Once you have music in front of you, read the first few notes before playing. You want to be able to read ahead and let your fingers follow your brain.
Keep in mind that speed is not the goal! Reading music correctly and playing every note correctly is the goal. Sight reading helps with learning how to read music because it allows you to practice seeing new notes in front of you without having read the music before.
It really takes practice to play the notes impressively like you may see on YouTube. There's no magic product that will miraculously teach you how to read fast and play piano perfectly. Look at it as if you were learning to drive a care. Begin slow and read the notes carefully and put thought into every key on the piano you press. In a few months, you would have built more confidence in your note reading that the time between reading the notes and pressing a key will decrease.
With patient practice of hitting the right notes, you will be less likely to make mistakes later!
You should always aim to practice playing piano and trying out new songs for at least an hour a day. My method of practice is to always go back and play old songs just to keep a repertoire. It will maintain your skill level and not waste all the work into mastering a song.
You will also become more impressive when you need to play in front of other people (which brings up - for songs you really like, you may want to memorize it so that you can play it on the spot)!