How do I add featured products to the homepage of my store?

The recommended way to add featured products to the homepage of your store is to use the 
aerocargo/listing-collections package.
Install
Run this command in the root of your project:
composer require aerocargo/listing-collections
Create a section
1. Create the file:
themes/acme/resources/sections/best-sellers.twig
Replace 
acme with the name of your theme.
2. Add the twig:
{% set collection = listings([{
    "tag_name.en": "Best Seller"
}], 8) %}
{% component "listings" with { listings: collection } csr %}
    <div class="aero-listing-collection">
        <h3 class="aero-listing-collection__title">Best Sellers</h3>
        <ul class="aero-listings grid grid-cols-4">
            <li v-for="listing in listings.data" class="aero-listing">
                {% snippet "listing-card" %}
            </li>
        </ul>
    </div>
{% endcomponent %}
Use the section
Reference your section where you'd like it to display and pass through the variables, here we'll use the tag name 
best-sellers this will be referenced in the next step.
{% section "best-sellers" %}
Now products tagged with 
best-sellers will be rendered wherever our section is used.
See more info in the 
aerocargo/listing-collections docs.