1. Double check your btc wallet address before making a transaction. This is the most important part because once there is a single letter or number that is missing, then that 1 btc is gone.
Not exactly. Bitcoin addresses have checksums incorporated into them. If you change a single character, the verification fails and the wallet shouldn't be able to send to that address or it will report it as invalid. You can test that yourself. Take any of your addresses (or someone else's) and paste them into a block explorer. You will see the history of all transactions. Now change one random character in the address and search for it again. You should get some type of error that the address doesn't exist. Even switching a lowercase character to an uppercase one will do the same in addresses where such changes are not allowed.