[bengarvey]

1. Use RI's (like you said) and make sure your utilization is high.

2. Look at any under utilized EC2 instances and make them smaller. If they are very under utilized, consider moving what they do to Lambda, which is very cheap.

3. S3 for everything storage. Only use EBS volumes when you need to.

4. Someone mentioned multiple availability zones and it's a great tip. Turning it on is 2x the price for RDS, and it's probably not needed for anything but critical instances.

5. Make sure unused instances are terminated, not stopped.

6. For very expensive systems, use spot instances to strategically reduces your costs when ec2 instances are cheaper.

7. Try to keep your instance types down to a few types. This will give you fewer headaches when you go to purchased reserved instances.