Day 13: Evocative Environments - I really work on this but too often when a fight starts that goes out the window.
Day 14: Compelling Characters - I try to come up with good backgrounds and goals with my characters, but I've found it can take a couple of months to really nail who the character is.
Day 15: Great Character Gear - We mostly play 5E so we usually have some cool stuff. My current character, Hadrian Bluehawk (Human Level 18 Fighter Champion) has some amazing stuff that boosts his Saves, gives me an AC of 25, and I have a damn cool long sword too.
Day 16: Quick to Learn - I learn game systems pretty quickly and I've always loved getting new RPGs. I remember getting the Champions 4E rulebook and finding a Magic of Palldium Books 'zine and immediately wanting to get Heroes Unlimited...I just love RPGs.
Day 17: An engaging RPG Community - My current fave is the Shadowdark FB Group.
Day 18: Memorable Moment in Play - Through shenanigans are group volunteered to take on a whole fortress of sahaguin and one of the players was invisible and scouting underwater on a flying broomstick. I had found a Deck of Many Things and while we waited in safety offered the caster a draw from the deck. Her sorcerer blinked out of existence and the scout became fully visible and had to high tail it out. Because of his haste he wasn't able to free a fish person being tortured and we all gave him heck about it even though he had no real ability to help without dying.
Day 19: Sensational Session - The session before the one above had us meeting with a town to figure out how to deal with the sahaguin who had taken over an old fortress nearby. I volunteered us, as the only character that went to the meeting, to storm the fortress all by our lonesome.
Day 20: Amazing Adventure - For me it was the second adventure of a Deadlands game we were playing about 2 years ago. I really felt that the players were doing a great job of fighting evil in the Weird West.
Day 21: Classic Campaign - I've always wanted to run Horror on the Orient Express. Maybe one day.
Day 22: Notable Non-Player Character - There was a charlatan and PC foil, a tiefling named Krent D'Midnite that I always enjoyed bringing on screen.
Day 23: Peerless Player - My buddy AJ, he always has great characters with fully detailed back stories and he always stays in character.
Day 24: Acclaimed Advice - No gaming is better than bad gaming.
Day 25: Desirable Dice - several companies make d4s that aren't those lousy caltrops. I love them.