What's a good way to avoid battling to get my baby to sleep?

Keep a routine. Have a bedtime routine. Remember babies learn by association, so if the last thing he remembers is being rocked to sleep, that is what he will expect as this is what he knows. Place the baby in his crib when he is sleepy and avoid rocking or feeding right before you put him to sleep. Help him develop self soothing skills. Be patient, he is just learning and it will take a bit of time.