I've been using AWS professionally for about three years now, and I only actually needed to study for a couple weeks to pass once I really got started. I also had never created a VPC or an EC2 Scaling Group before a couple weeks ago. So it's not like I didn't have anything to learn.
I started my training with the A Cloud Guru course on Udemy. Their training is really top-notch, and they provide all of their associate level courses on Udemy--which you can pick up for $12 on sale. That's also how I studied for the Developer Associate exam, and it's how I'll be studying for the SysOps Administrator certification.
Next I purchased the WhizLabs Practice Tests for the exam. I've tried several practice exam resources in the past (including from aws.training) and these seem to be the best value. After taking the exam, you can look at all of the questions that you got wrong and it provides detailed explanations for why each answer is correct/incorrect.
I would say my final step was to schedule the exam, but that was actually the most important. I've been "studying" for this exam for a few years and I just keep on putting it off. Once I scheduled the exam I was committed, and suddenly studying became a high priority. And now I've got another cool badge for linkedIn, and--more importantly--some new AWS skills.