This is not an all encompassing list, but some helpful pointers before you get started.
Do
Take your time and make sure you will not be rushed the first few times you use your straight razor.
Read up as much as you can, and ideally read this guide, and watch the youtube video of me shaving with a straight razor before trying your first straight razor shave.
Make sure you properly prep your beard--wash your face with a cleanser, and use a hot towel or splash warm/hot water on your face to soften your beard hair.
Use a shaving brush to raise the hair on your face, and build a thick/rich lather on your face. Take extra time to really work it in, and let the cream/soap you are using soften your beard.
Take small/short strokes--confident strokes. Unlike a DE razor, you will feel feedback from the razor cutting your beard. Hold the razor firmly (not OVERLY firm or tight, but hold it knowing if you drop it, it'll ruin the razor, and potentially hurt you) and be confident in your short/quick strokes.
Thoroughly dry your hands before picking up your razor. You don't want slippery hands!
STRETCH THE SKIN! Stretching your skin, and pulling it taut is essential to getting a close, and effective shave. There is no safety bar, or plastic fins to pull your skin taut for you like there is with a cartridge razor or a DE.
Have fun!
Don't
EVER, EVER, EVER move the blade horizontally on your face. With a 3-inch devilishly sharp blade on your face, ANY horizontal movement will result in a serious cut.
Forget to watch the tip of the blade. You may be so busy stretching your skin, and trying not to cut yourself, you forget to watch the tip of the blade. You do NOT want to detach your earlobe from your head, or slice into your nostril, or worse yet, if you have a spike, catch it into the side of your cheek. YIKES!
Rush yourself. This is NOT a race. If it takes you an hour to master your first straight razor shave, there's no shame in it. Take your time, relax, and enjoy yourself.
Push yourself. If you are doing well, don't push it. Master the basics before you start shaving against the grain, and doing more complex maneuvers.
Use another type of razor (DE, Electric, Cartridge) to touch up areas you might not have done too well in. This is counter-productive to you learning how to properly tackle all areas of your face.
Be afraid to ask questions. We were ALL beginners at once. While you may think your question is silly/stupid, every one of us more than likely had the same question at one point or another, and I assure you, sounding silly on a forum is not nearly as embarrassing as walking around with toilet paper on your face, absorbing the blood for the cut on your face.
Give up. Straight razor shaving is not dangerous or for that matter, all that difficult, but it DOES have a steep/long learning curve. If you've read the entire guide up until this point, likely you have the desire to really succeed. If you don't get the results you want in a week, or a month, be patient--it can take months!