Infants who sleep on their back or side often develop crawling later than normal. Need lots of room to explore. This is the year of exploration. Child-proofing is a must now, and constant supervision must always be given. Need to be told what TO DO instead of what not to do.
Positive words is the key here.
When your child gets into something he should not, gently say that that is not a good choice and remove him from the activity or object. Rules and consequences need to be the same all the time. If the child knows what to expect he is more likely to behave appropriately. Actions speak louder than words. Show your child how to behave.