Ensuring integrity and confidentiality together with symmetric encryption
Do not invent your own authenticated encryption mode. Use a standardized one, and use a well-supported library to implement it in your code.

AES-GCM, AES-CCM, AES-OCB, and AES-CBC with HMAC-SHA256 over the ciphertext are all common options.

Some great direction from Matt Green here: How to choose an Authenticated Encryption mode