weight loss while breastfeeding?

what tips can you give me to lose the pregnancy pounds now that i’m breastfeeding. i still have to eat 500 extra calories a day to provide for my baby’s nutrition, so keep that in mind. cant do too vigorous exercise either b/c i’m very heavy chested (even before i was pregnant, now i’m even worse!) so good exercise ideas welcome too if you can keep that in mind.
(sorry the wording is all jumbled, i’m in a hurry.)

I suggest if you are past six weeks post partum that you swim! You’re weightless in water which would eliminate your heavy chest issue.

Weight Loss Exercise Program Week 1