My backyard is about 1 acre but it has poor drainage. What can I do?

French drain is supposed to be very effective and budget friendly

Get consults with landscape architects about regrading the property. You want to drain away from your home but not onto the neighbors property. Drains may be required. Check local building codes too.

French drains are easy.

Consider grading it to a rain garden. There is a lot of information about rain gardens on the internet, and This Old House has done some segments on it, too.

You can amend your soil, also dig drainage line. You can rent a ditch witch and dig a trench or more at the low spots. Then put gravel in bottom. Lay a pipe in the ditch (pipe will need holes to drain. Then gravel to cover and soil back over that. French drain. We did that in our back yard and has saved us a couple of times.

Ya regarding may be the best bet. If you have a septic system make sure anyone who does work knows where the lines are