Throughout my career, I've been sponsored by several different equipment companies - Lynx, Titleist, Callaway.
I prefer old-world wines like Lafite Rothschild and Margaux.
Some players like to change clubs around the green to hit high or low shots. I play all of my short-game shots with my 54-degree sand wedge and change my ball position to hit it higher or lower. I think it's easier to learn one club than four.
The biggest mistake is trying to pinch down on the ball and ripping out a big divot, often hitting the ground before the ball. You'll dig up some turf, but you won't create much backspin.
Grip pressure - not mechanical flaws - is the biggest factor when you're nervous. You unconsciously grip it tighter, which keeps you from making a smooth swing with a natural release. Keep your grip pressure light, and you'll be surprised how much your mechanics stabilize.
When you get to the tee on a really long par 5, I know what you're feeling. You want to let the shaft out on the driver and try to bomb it down there. I get the same feeling. But a big tee shot is not always the best strategy, especially on a long hole.