I used to have lousy vibrato long time ago. A good friend of mine told me to improve it by putting pressure on your thumb against the back of the neck. I know this goes against all the Eric Clapton schools of free hand vibrato'ing (shaking the entire hand thing without any thumb brace). If you have a good solid pivot point start by over exaggerating your string bends real slow and purposefully. Make it sound out of tune on purpose. Bend up towards your head then let down. Do it over and over slowly then stop and forget about it. Go back later on and do it again. Eventually your brain will know what to do and you'll improve. Vibrato is a change in pitch usually the note played and the next half, full step up in pitch or more. The speed between pitch changes is what your brain will get accustomed to. Get that idea fixed in your mind and you'll get it.
Guitars/Bass - MIM Fender Classic 50s Strat, MIM Fender Standard Strat, Squier Classic Vibe 50s Tele, Gibson Les Paul Studio, Epi '56 Gold Top Les Paul, Martin DSR acoustic, Sigma Martin Auditorium electric/acoustic, Squier Jazz Bass.
Amps/Cabinets/Modelers - Model 2558 50 watt Marshall Silver Anniversary Jubilee combo w/ Celestion Vintage 30s, 4x12 Marshall cabinet w/25 watt Greenback Celestions, Fender Blues Junior w/ a couple of Billm mods, Line 6 POD 2.0, Roland Micro Cube
Pedals/Effects - Cry Baby Classic Wah, Boss TU-2, Boss NS-2, Boss RC-2 Loop Station, Ross Compressor, MXR Micro Amp, Danelectro FAB Echo, Danelectro FAB Chorus, Danelectro Chicken Salad, Marshall Guv'nor Plus, Marshall Echohead, Duhvoodooman's Zonkin' Yellow Screamer, Digitech Digiverb, Digitech Bad Monkey, Dunlop Fuzz Face, Homemade Loop Bypass pedal, Duhvoodooman's Sonic Tonic (Maxon SD-9 clone +), Voodoo Labs Superfuzz