On the Laravel News site they've posted a tutorial sharing some of the basics around the optimizing Eloquent queries with the help of its own "eager loading" feature.

Object Relational mapping (ORM) makes working with databases amazingly simple. While defining database relationships in an object-oriented way makes it easy to query related model data, developers might not pay attention to the underlying database calls.

A standard database optimization for an ORM is eager-loading related data. We will set up some example relationships and then walk through how queries change with and without eager loading. I like to get my hands directly on code and experiment with things, and I hope to illustrate how eager loading works with some examples will further help you understand how to optimize your queries.

They start with a classic example of the "N+1 problem" when working with database records and how, without you knowing, you might be causing it with lazy loading. The article then talks about eager loading vs lazy loading and how they differ in most ORMs. It then covers Eloquent, setting up some migrations for an example blog application and creating the relationships between Author (user) and the Posts. The models are created and seeders are built to populate the tables with Faker data. Finally it gets to the use of eager loading, making use of the "with" functionality to modify the query structure behind the scenes. The post finishes with mentions of two other eager loading types - lazy eager loading and nested eager loading.

Luciano Mammino has posted six tips for blazing fast web applications to his site. These tips aren't as much specific to the code (though they're related) as they are general good practices around architecture, development work and common issues.

In this post I will try to highlight some of the most common principles that you have to take under consideration when you want to achieve a great level of performance while building a web application (specifically on the backend part). I believe the concepts discussed here can be applied to any language and framework even if, due to my specific experience, I will mention some examples, design patterns, conventions and tools that are mostly used in the PHP world.

His post lists out six main rules along with some description and links to other tools for each:

• Avoid premature optimization
• Do the minimum amount of work to solve the problem
• Defer the work you don't need to do immediately
• Use cache when you can
• Understand and avoid the N+1 query problem with relational databases
• Prepare your app for horizontal scalability when possible

There's lots of good tools mentioned here so find one that fits your needs and helps solve the issue. There's also some good articles mentioned, giving more information about a particular topic or other perspectives on how to solve it a different way.