Spot Seeding: Or patch seeding is done to repair small damaged areas.

Be sure to rake up any debris, then lightly loosen the top 1 inch of soil, level properly, spread the proper amount of seed, step on it to ensure firm contact with soil, keep moist until established.

Sodding:  (how-to picture sequence to be provided with commentary)

Dethatching:  Only required in extreme circumstances where grass has gotten to the point that it requires mechanical intervention.  Regular Aeration and proper care prevents thatch build up from ever getting this far.

Dog Damage
If you own a dog, then you already know what the scruffy little fella can do to your lawn!
Not to worry, We can Help!

Understanding the problem: Simply put, whether male or female, dog urine of either sex, and any breed can burn your lawn when deposited directly in one spot.  Dogs that squat tend to concentrate their urine in one location when they pee, thus creating the problem.

Dog urine contains a high amount of nitrates- in other words nitrogen.  Nitrogen makes your lawn green, however if there is too much, it can burn.  This is why you get yellow circles on your lawn.  You'll also notice the middle of these circles are yellow (burnt) but their is a deep dark green ring surrounding it.  This is because, as the dog urine dissipates outward from the centre, some spots get too much nitrogen, some get just the right amount creating a perfect green circle, and the rest blends into the rest of the lawn.

Prevention: The best way to prevent dog damage is to try to train your dog to do its business in one specific area.  It may not be practical, and may be easier with younger pups, however this addresses the source of the problem.

Repair: During the summer, diluting the area with water while the urine is fresh should cause it to dissipate before it has a chance to burn the roots.  If you are attempting to repair the area after a long winter Follow these five steps:
Step 1: Rake each area thoroughly.
Step 2: Dilute the area with a long deep, watering.  In fact, several deep waterings is best before proceeding with the next steps. (you need to dilute the nitrates bound to the soil particles & help them move past the root system)
Step 3: Apply Lime Soil Conditioner.
Step 4: Scratch up the existing soil and blend in an alkaline soil mix. (urine is acidic)
Step 5: Apply seed to the area and ensure firm contact with soil.  Keep seed moist until established.