Painting: Lessons I've Learned from Mistakes I've Made

I've posted about my paint debacle before here, but I spent even more time this weekend repainting the walls I worked so hard to paint once already! This weekend, it was the entry's turn to go from a semi-gloss finish to a flat finish:

I also repainted the stairs. They just weren't WHITE enough! A lot of the ugly yellowish paint that was there originally was showing through, as was some of the stain from when we had the steps refinished. Basically it just needed a facelift. Here is an in-progress shot (After taping, before painting):

While I was repainting, I thought about how much more confident I am when painting and all of the lessons that I've learned. The most interesting thing I learned about being a good painter has nothing to do with skill or tricks-of-the-trade, but just about making sure I'm awake, focused, prepared, and up for the job! That being said, here are my painting tips:

• Prep the night before you paint! This includes getting out your drop-cloth, brushes, paint cans, stir sticks, rollers, and painters tape the night before. I actually even prefer to tape everything the night before as well. This can take a really long time (for me, often longer than painting a coat!) so I try to break up the prep and the painting between days so I'm not tired before I even start with the paintbrush. If I'm tired, I am sloppy and careless!
• Eat a solid snack or a good meal before painting. I find that if I get hungry an hour into painting a room, I start to get tired, I lose energy, and therefore, once again, I start to get sloppy! (I swear sleeping and eating are the good to a key paint job!)
• About an hour into painting, stop and clean your brush and your hands. As you may have picked up on, I can be a little bit sloppy at times (!!), but, I also have surfaces I do NOT want to get paint on so I have to be careful. The best thing I have found to do this is to STOP and wash up every hour or so. This way my brush isn't dripping the excess paint that starts to accumulate near the base, and I'm not making handprints or elbow-prints across the walls with the paint that's gotten on my hands (or elbows)
• And in case the above doesn't work... Always, ALWAYS, carry a wet-paper towel in one hand while painting. If you are messy as I am, this is essential to quickly wipe-up drops on your trim or beautiful floors! I've also found if you put just a dap of dishsoap on the papertowel too, it works even better.
• Paint in natural light. You can see your strokes and lines so much more clearly and this often leads to a better paint job. I typically always try to paint first thing in the morning when my house is nice and bright! 
• When painting with primer, as I often do, I try to wear long sleeves and pants, and sometimes even gloves. I use Killz primer whenever I have the need, and the stuff is great but its HARD to get off your skin! I have sensitive skin, and scrubbing endlessly to remove the paint is painful and time consuming!  I won't do it anymore - long sleeves it is!
• Understand that painters tape is not God's gift to painters no matter how much those paint commercials try to sell it! It's a lie! It helps, but it is not perfect by any means and can be very frustrating if you are expecting amazing results.  The best way I've found to use it successfully not to go directly to the taped area right after you load your brush with paint. Paint in the middle wall of the first, and then when your brush is nearly dry, THEN go near the area that is taped. This will hopefully help you prevent excess paint from seeping through the tape.
• I prefer the 1.5" Scotch Blue Delicate Surface tape with Edge Lock.
• Always REMOVE any outlet covers or switchplates before painting. Do NOT tape over them or try to paint around them. The result is soo much better if you remove them, paint, and then put them back on. (Trust me, I know from experience!)
• I buy a lot of Sherwin Williams paints.. Every once in awhile, they have a big paint sale where cans are 30% off. Even if I don't need paint that current moment, sometimes I'll buy a few gallons and stock up, and then bring them to be mixed later when I figure out what project (and color!) I need next! This way I take advantage of the sale but am not committed to a color yet!
• For keeping track of your paint colors (especially custom mixes), I take a picture of the top of my cans that show that color mix. I keep it on my iPhone, this way I always have the 'recipe' for the color handy when I'm out and about!

• Always apply two coats. Always!
• If you can, remove your baseboards if you plan on painting the room and your baseboards at the same time. Having a real nice, clean line between the room and the trim makes the room look so much more crisp! I painted my baseboards without removing them, and the line isn't 100% perfect and to be honest it drives me a little crazy! (Hence the reason I plan on slowly replacing all the baseboards in my house!)
• My favorite brush is a 2" angled brush with a short handle. It is my go-to for painting trim, for painting edges, for getting in tight corners, for painting furniture... the list goes on and on. I have about 10 of these and rarely ever use any other kind of brush! 
• And my number one rule... If you have plaster walls, use a FLAT paint!!!!! (This will hide the blemishes and look a million times better!)

I think thats it! :) Any other tips to share? Especially regarding painting ceilings? That is next on my list!