In order to answer what makes someone a great wide receiver, let's first define some of the wide receiver's responsibilities. A wide receiver is responsible for catching passes and running various routes down the field. He is usually positioned near the sidelines. To better understand what qualities good receiver has, let's go step by step through a passing play, and see what skills receivers need to be great.
Like the other players on offense, the receivers must stay behind the line of scrimmage before the snap. A great receiver has a great stance that will allow him to explode into his running route and gain speed to create separation from the defender. In an initial stance the wide receiver will have one foot back, knees bent slightly in front of the front toes, most of his weight on the front foot, a leaning forward upper body posture, and ready hands. Mastering the initial stance is the first step for a great wide receiver.
After the snap, the receiver will be inevitably defended by the opponent. In order to get free to receive a pass, the wide receiver must create separation from the defender using body feints, and footwork. Great receivers have great footwork and great use of their bodies and can easily get by defenders getting free for the pass.
The after creating separation from the defender, the receiver must know the game plan thoroughly, so they know which route he is supposed to be running and when. Routes will always change, so it's imperative that the receivers know all running routes in the route tree. When running, it is also important to be able to execute each run properly, where the previously talked footwork will come in handy again when running any pattern that requires a sudden stop or change of direction.
Great receivers must catch the easy and the hard passes. For that, they have to have exceptional body control and good hand positioning. Although it may seem like catching passes depends a lot on talent, even the most talented players like Odell Beckham Jr and Antonio Brown practice their catching skills a lot. It is also needed to have good timing with the quarterback and a lot of awareness, especially when catching a pass near the sidelines.
After catching the ball, the receiver may have to run and escape a few tackle attempts, and defensive players in order to get to the end zone. For that, it is again necessary to have great footwork, body control, and other physical aspects.
Besides all those skills mentioned above, being a great receiver requires a lot physically. Wide receivers seem to be always running to catch a pass, and then running again towards the end zone. They are also always being tackled and taking strong hits. Because of this, receivers must have a lot of stamina.
Knowing all body feints and footwork is useless if the receiver can't execute the moves in a fast and agile way. Speed and agility are probably the two most important physical aspects for wide receivers, as basically every aspect of their job on the field needs that.
In addition, Receivers must be able to jump, and jump high. Preferably higher than the defender. That will allow him to catch harder passes, those who may be thrown very far down the field, or by a pressured quarterback.
By extensively practicing the technical and physical aspects, a good wide receiver can become a great wide receiver.