Tips for how to be a better DM- Things i watch
As a DM you want to use all the material available to you to make your world what you wanted to be and to learn how to be the best DM you can. Below is a list of different things that I and other DM's use to get reference it's a good way to study other DMS and learn the things that you like about them and the things you would change and then Implement that into your game me personally I don't use all of these but I thought I'd be helpful for new DMs.
Admittedly my favorite thing to watch is Matt Mercer DMing on critical role. Which can be found here https://geekandsundry.com I also really like web DM that's my second choice. The link is below.
WEB SITES & BLOGS
World Builder Blog - https://worldbuilderblog.me/
Sly Flourish - http://slyflourish.com/
DMs Guild - http://www.dmsguild.com/
Stan Shinn - http://swshinn.com/
Official D&D Resources - http://dnd.wizards.com/products/tabletop-games/trpg-resources
Kobold Fight Club - https://kobold.club/fight/#/encounter-builder
Reddit D&D 5e (aka Next) - https://www.reddit.com/r/dndnext/
Reddit D&D - https://www.reddit.com/r/DungeonsAndDragons/
YOU TUBE
Matt Colville - https://www.youtube.com/channel/UCkVdb9Yr8fc05_VbAVfskCA
Roll20 - https://www.youtube.com/channel/UCHC1kWACzA7G6D2fqkqsRDg
Official D&D channel - https://www.youtube.com/channel/UCi-PULMg2eD_v5AO0PlW4sg
WASD20 - https://www.youtube.com/channel/UCQOmmyopiTzH9dlThm8hbwQ
WebDM - https://www.youtube.com/channel/UC7XFmdssWgaPzGyGbKk8GaQ
Nerdacrhy - https://www.youtube.com/user/Nerdarchy
How to be a great game master - https://www.youtube.com/user/Bon3zmann
GM Tips (Matt Mercer & Satine Phoenix) - https://www.youtube.com/playlist?list=PL7atuZxmT9570U87GhK_20NcbxM43vkom
My #1 tip for DMs looking to improve is to only make your players roll when you feel that their character would struggle at doing the action. For example, the Ranger is lighting a fire when setting up camp in the wilderness, making them roll a survival check wouldn't make much sense and would only slow down the game. But in a situation where a rogue is picking someone's pockets, obviously make them roll a sleight of hand check because failure could actually progress the story and not slow it down.
One of the most useful advice-series on YouTube in my opinion is Adam Koebel's Office Hours, where he answers concrete questions, rather than giving generic advice.
In the end all problems boil down to three things: