Let us now examine this deployment one component at a time, starting with the VPC itself.
I am proceeding under the assumption that if you are still holding this book, you have likely accepted the way of the VPC.
How many VPCs are you foreseeing having? Would they be linked (VPC peering) or would you be bridging other networks in (VPN)?
The answers to these questions play a role when choosing the CIDR for a VPC. As a general rule it is recommended to avoid common (household router) network addresses such as
Keep track of and assign different CIDRs if you have more than one VPC, even if you don't have an immediate need to peer them.
Consider a CIDR that will allow for large enough subnets to accommodate potential instance scaling with minimal fragmentation (number of subnets).