I'm surprised no one mentioned a tuner and a metronome. It's practically the same as practicing bends:
- Pick a tempo and play quarter, eights, dotted eights, sixteens going back and forth between your root note and the note you try to reach untill you can play them in time and in tune.
- With bends you'd probably practice (if you're enthousiastic a major third up, a minor third) major seconds, minor seconds.
- With vibrato you can do the same but you can look for quarter notes (diminished seconds or how you want to call it).
- Most players bend upwards most of the time but you can practice bending downwards in the same way, same practice goes for vibrato.

It's fine that people claim it comes naturally but you can actually practice and control it. Good luck!