There are a lot of people who wish to get started with Ruby and Rails, but don't know where to start. I hope that this post will serve as a guide for those people.
People try to develop Ruby and Ruby on Rails apps on Windows and they struggle with it. You can try developing on it, but know that it's going to be more painful than the other options (Linux or Mac).
It's for this reason that I recommend installing Ubuntu in a VM (using VirtualBox) on your Windows PC if you're in that environment.
Once you've got Ubuntu setup, you can follow my Ubuntu, Ruby, ruby-install, chruby, Rails and You blog post which will setup a proper development environment for you on Ubuntu.
If you're on Mac, you can follow many of the same steps in the Ubuntu guide. Install ruby-install, chruby as per that guide, and then you can install Homebrew, and then install PostgreSQL by running this command:
brew install postgresql
Or MySQL with this:
brew install mysql
Getting started with Ruby
The Ruby Koans
Your environment is now setup and now you're wondering where to go from here. I always recommend the Ruby Koans which, as their site says:
The Koans walk you along the path to enlightenment in order to learn Ruby. The goal is to learn the Ruby language, syntax, structure, and some common functions and libraries. We also teach you culture. Testing is not just something we pay lip service to, but something we live. It is essential in your quest to learn and do great things in the language.
The Koans are a fantastic introduction to Ruby and if I had my way, it'd be where all newbies started to learn. You don't have to complete them all, just try your best. It's time I admitted: I've never actually completed the Koans myself. One day I might.
The Well-Grounded Rubyist
If a book is more your style, then The Well-Grounded Rubyist is the one that I would recommend. The very first version of this book (Ruby for Rails) is what I learned Ruby from. I don't link to it here because it was out of date when I read it and that makes it even more out of date now.
Jumpstart Labs Tutorials
I also recommend checking out the Jumpstart Labs Tutorials, which are written by the people who run Turing Academy. These include tutorials that will introduce you to Ruby in 100 minutes, as well as some Sinatra and Rails tutorials so that you can wrap your head around applying Ruby to web development.
Getting started with Rails
Rails 4 in Action
It'd be remiss of me to not mention my own book, Rails 4 in Action in this section. In the book, we build a ticket-tracking application from the ground up using Behaviour Driven Development. Thousands of people have found it to be a great introduction to Rails, and some people have even gotten Rails jobs after having read it.
If you don't want to shell out the money for my book (and why not?!), then the free Rails Tutorial is the next-best-thing. In that tutorial, you build a Twitter-like application from scratch.
More reading / viewing / listening
Before you go ahead and read this list, you should take some time to go through the resources above and gain a basic understanding of Ruby + Rails. Consider these supplementary to the above list.
If you think of anything that should be added to this post, please leave a comment.