If you have built your entire infrastructure with CloudFormation you could more easily replicate it, even in another account.
You still need to deal with data migration, which will be different depending on your deployment setup.
If you use configuration management most if not all of your OS can be replicated in your other account too.
While AWS does have a method of reverse engineering a CloudFormation template based on your current environment I've never tried it, sounds like you should give it a go.
The aws cli has commands to move s3 data "aws s3 sync s3://from s3://to". You may need to export or otherwise share other data like RDS and SNS.
SQS
Create a new SQS queue and point code/configuration at it. Alternatively, you can enable cross-account delegation (though this doesn't change ownership).
EC2
Running instances cannot be moved. Either create new instances and reprovision them (with, say, ansible/salt/puppet/chef) or create an AMI of the EC2, share the ami, and relaunch.
RDS
RDS instances can't be copied. You will need to extract the data and transfer it to a new database instance.
S3
Buckets cannot be moved between accounts. You can copy data into a new bucket or enable cross-account delegation (though this doesn't change ownership).