UI

This is how mechanically to play KoL, and where you should be looking on the screen. Unfortunately, there is no TL;DR of this.

Overview
This is the KoL UI, with crucial areas highlighted in order of importance. This is how to be more aware of what happens during a match, and how to avoid some common pitfalls and bad habits.

1. Control Groups
Control groups are the most important tool in your arsenal. Using control group hotkeys is one of the best ways to become a faster player, and speed is the name of the game. In a nutshell, each control group is a selection of units that you can press the 1-9 keys to immediately select, anywhere on the map. Pressing the key twice will center the camera over those units. A simple method of using control groups is to start by hotkeying all your Town Halls to the same control group, and pressing that hotkey every few seconds to be sure you're making Workers.

You may also utilize camera hotkeys to immediately move the screen to locations of your choosing. You should only "bump" the camera around by moving the mouse to the edge of the screen when absolutely necessary. Everything else, you should have a camera hotkey for. Make a camera hotkey for each base, for the front you plan to attack on, for areas you drop in. You should have as many camera hotkeys as you can realistically make use of.

2. Minimap
This minimap shows troop movement anywhere that you have vision of. You should be glancing at the minimap every few seconds to check for surprise attacks. Think of this as your rear view mirror. If you follow the advice above and check your bases every few seconds to be sure they're making workers, add checking the minimap to the end of that cycle.

3. Timer
Most new players flat out ignore the timer, not caring how long matches are. That's not what the timer exists for. By studying the build times of structures and units, you can begin to form a framework of what is and isn't possible in a game, and create Build Orders around that. If you know what your opponent is mathematically capable and incapable of based on the timer, you're a much more prepared player.

4. Resource Monitor
These are the Mineral, Vespene Gas, and Supply counters. You should know the rough amount of Minerals/Gas you have stockpiled, and how much open Supply you have. It's good practice to constantly be making Workers and Supply structures, which will always leave you with open Supply for units, and a healthy income.

5. Unit Info
The unit info section is something to be checked as often as possible, but it's not your unit info section you need to watch. Learning how much Armor your units have, and the Unit Tag, should be memorized. You need to keep an eye on the enemy unit info section, to know how and when he's upgrading his units.

6. Command Card
This is where you can click on buttons to issue commands to your units. This is a trap new players fall into, creating bad habits. Never click on this, use the corresponding hotkey abilities instead. For example, A is the hotkey for attacking. Never click on any of the buttons on the Command Card.