I just bought a house in April and now I have to start taking care of my lawn...

What should I start with? I'm not sure what I need to do besides mowing it... It is April, so what do you usually do for lawns now? I'm a NEWBIE to this...
I live in Rochester, NY..

Thanks!

There are a number of things you can do to improve the quality of lawn and to maintain it in good condition:

Aeration
Lawns need to breathe. Invest in an aerator or garden fork to place holes in the ground. Aeration is usually done twice a year (ideally on a cool day when fertilizer can be added), during the growing seasons of spring and fall. Make sure you give the holes a good twist to let the air in. Add a little peat moss to stop the holes from closing up.

Mowing
If you cut the lawn too short, this encourages growth of weeds. Weeds cannot grow if the lawn is thick and lush as there is no space for them to grow.

Fertilizing

This should be done twice a year. If you do not add fertilizer, weeds will thrive. Excessive fertilizing can cause brown patches and lack of colour as the lawn can turn acidic. There are PH tester kits available. Also acid loving plants such as hydrangeas turn from pink to blue in acid soil. Purchase some lime or dolomite and lightly and evenly spread it over the lawn if this happens.

Lawns love seaweed extract products as it helps their root growth. Give extra attention to places where trees grow. They are thirsty so need extra water and fertilizer around the canopy area. The addition of iron chelates gives a nice green colour to yellowing lawns.

Watering
Excessive watering brings roots of the grass to the surface and they become too reliant on constant feeding. Also pests such as lawn grubs can eat the lawn. You will need to spray to kill them. Try to strike a balance. Avoid watering the lawn for a while then give it a thoroughly good soaking to encourage root growth.
After roots are established you should not need to water for a week, unless there is a particularly hot day.

Weeding
Weeds are going to grow no matter what, it just depends on how many you want in your garden. So good old fahioned manual labour in weeding is necessary.