I feel like I've been reading many of the same types of questions and just thought I'd put a post out there with some things I've found in my limited and new brewing experience. I'm trying to keep things vague and basic, but please hop on!
1) UV light skunks hopped beverages, only after fermentation begins. Our friends here at HBT have instructed me that riboflaven needs to be present also for skunking which only happens during fermentation. Direct sunlight contains the most, but indirect (depending on reflective surfaces) and fluorescent lights (like those in commercial places) can also expose the beer to enough UV to cause skunking. Covering clear carboys is a good idea. Keeping them in a dark place is the best.
2) Blow off tubes are fantastic. They don't cost much and fit right on your carboy. I've never had to worry about an air lock shooting for the moon, then cleaning and sanitizing it, and putting it back on before anything can get in the carboy.
3) Properly dissolved Iodophor (1/2 tablespoon per gallon for mine) is a no rinse sanitizer. As strong as it smells, I cannot taste it in my beer and I know my bottles are good to go when bottling.
4) Extracts do not require a full boil, as a full boil can darken it and subtly change it's flavors. By full boil I am referring to the length of time, though a full volume of water boil is not required either (It's not the best, but you can top off the primary with water). Boiling it the full time is just an option you have. I've added my extract late in the boil (last 15 mins) and found a remarkable change in finished color in my beer. It was much lighter.
5) Invest in a hydrometer and wine thief! They do not cost much, and I'm sure you'd hate to be the guy who can't tell when his beer is done fermenting. There are clues for active fermentation, but without the proper measuring tool (that would be the hydrometer) there's no way of knowing for sure. (note: hydrometers don't care if there are particles in the wort floating around, they only read the density of the dissolved material)
6) Mistakes have happened in almost every brew I've ever made, including 2 batches of beer, 3 batches of cider, and 6 batches of wine. Many of them were caused by being impatient, some of them were just honest mistakes. All of them still turned out better than Bud/Coors or night train. One of them was a memorable raspberry wine I'll never forget.
7) I'm sure we've all probably read beer can be brewed in a month. 2 weeks to ferment, 2 weeks to bottle condition. Turns out it's more like it should be AT LEAST SIX WEEKS: 3 for fermenting and clearing, 3 for bottle conditioning. Some brewers even insist on at least an additional week for letting the bottles chill in a fridge before serving (for clearing and carbonation purposes). I speak from experience when impatience drove me to bottle too soon (just over two weeks) and now I'll be thinking about all the excess yeast that will be at the bottom of all my finished bottles. Also, take two specific gravity readings a few days a part at the end to make sure the specific gravity is the same and it has terminated fermenting. Who really wants to deal with bottle explosions?
8) I've learned the hard way not to cut corners. If you see some black bits on the walls of the 6 gallon better bottle that you haven't used in 4 years, it's probably not good. Vinegar and vodka will not kill it. If it's visible and in there it will spoil your brew. It was heart breaking dumping a 6 gallon cider batch with a bacterial infection. $36 dollars and 4 months down the drain. Filling it up with water, putting 5/8 cup of unscented oxyclean in there and letting it sit for a few days gets it out no problem. rinse well and you're good to go.
9) I'll make this my last, though there are more. A new homebrewer doesn't need to worry so much. Do your best cleaning your equipment without going nuts, sanitize everything that contacts your beer as best you can and rest easy. My favorite part of my homebrew book was the part that mentioned how beer was brewed for thousands of years without even understanding the importance of sanitation, or even what yeast was.
Cheers to HBT!