As someone who has never GMed yet, but is writing a campaign I just cant get out of my head, I understand not feeling ready for the task. But let me say, you wont be ready. Your best placed plans, your crazy ideas, will fall short of what the players do. Your players have to be in agreement of what this campaign is going to be. If someone wants dungeon crawl after dungeon crawl, and the others want that rarely, you wont have a stable group, at some point, that one player will distrupt the game, and typically effecting the group as a whole. Because you are telling a story with your players. How you react to the story and how they react is part of the adventure you both have. The biggest pitful I see is that it can become a GM vs Player mentality and if it gets there, you are doing it wrong. You both should be working together to make a story, if this isn't happening, the group in whole or part is not suitable for the table, and its on the GM to see this and make the hard choices of how to fix it. Sometimes this means someone stepping away from the table. Your players must be invested in this campaign, the time and effort it takes a "at the table" GM can quite easily be doubled when it comes to doing it online, because of this if your players are not invested, your time investment value becomes diluted. Anything you wish you were told before your first game? Don't plan for how your players will react to the campaign arc you are setting up. Prepare for things to go well, bad and inbetween, have escapes ready and have problems at hand. How would an enemy of the party react to them trying to make friends and trying to put aside problems for a greater good? Does that truely benefit the other party as much as it does the players? Will letting the players have this make the arc better? How do you make sure a custom game is scaled right for a group of players? Your rolling should be done in private 99% of the time, and when you are making public roles its for a good reason. You should know what hits your players and should target them using the creatures understanding of the world. If that is not possible use dice to decide what they do (Typically attack). How do you prevent TPK? I might be wrong on this, as I've never GMed. But, my honest feeling is you shouldn't. It's the players who decide if they should run or not. Let them feel fear as they are being picked off one by one, if they finally decide to flee, give them that advantage. That doesn't mean a penalty cannot be done later on down the track, but, at least they live, and can heal the wounds. Or, the enemy of my enemy is my friend , could come in at the right time to save the day. Any techniques that you have discovered in roll20? Don't be shy of not having maps. Forcing the player to see what is happening in their minds eye keeps them engaged, makes them think a bit more, and can increase roleplay viablity. That said, if you make a map, go do so with the intent of making it look good for the situatition it calls for. A random camp is fine to have squiggles and stickmen, a dungeon crawl should have decorations and backgrounds, a torture room should have sound effects. These all bring the user into the world and enviroment you create. Don't be affaird to use non-visual maps. Further don't be shy of forcing the players to create maps. Be leanant on what is correct and what isn't, and don't forget there should be ways to reward nice player maps. Know and understand macros. Check your players honesty, macros rolled only report what the player tells it to roll, it doesnt make sure they are correct. How much control do you give players over their own tokens? 100% control. It's their character and the moment you take away from them is the moment you have lost. Unless this is stated at the forefront of the game, then having anything less than full control is a restriction many players don't like. Tabletop Roleplaying is liked in my view because its typically open content free from player restraints. Say I have a weapon rack that has a weapon free to take, do I make the art a background piece or a token? A token is something that can interact with itself, its surroundings or others. If a creature, object or npc has intelligence, its a token. If you create a character sheet for it, its a token. If you create something, and it doesnt need a character sheet, cannot interact with others on its own accord, its more likely to be a map sprite and having it on the map layer is the best place. Final words At the end of the day, you and the players you select are telling a story together. Rule 0 of the GM handbook typically says that you make all the rules you like. However, Rule -1 says that if the players dont like your rules, they wont play at your table. Find out what is fun for you, and fun for them, ask for the materity and respect of them to handle their characters as precious things, and that while you wont stop them from dying, you do have their best interests at heart. Learn in the moment, and learn from the actions and inactions both you and your group face. It will all make it better in the long run. The maps you worked on for two full days that where never used aren't wasted. Just put the maps to another location, or simply lead the players back to that location later on down the path, perhaps for different reasons. Either way, players will never know xD