LitElement's pre-requisites are Node.js, npm, and Polymer CLI.

Install Polymer CLI:

npm install -g polymer-cli

Create a new LitElement project:

mkdir myproject
cd myproject
npm init -y
npm install --save @polymer/lit-element
npm install --save @webcomponents/webcomponentsjs

Create a polymer.json config file, and serve your project:

cd myproject
npm install
echo '{
  "npm": true,
  "moduleResolution": "node",
  "entrypoint": "src/index.html",
  "shell": "src/my-project.js",
  "extraDependencies": [
  "builds": [{
    "name": "mybuild",
    "bundle": true,
    "js": {
      "minify": true
}' >polymer.json
polymer serve

Build your project, and serve the build locally:

cd myproject
polymer build
polymer serve build/mybuild