It's almost time for the leaf-peepers. Perfect timing - mix in the fall leaves with clippings, roughly 50-50, until you run out of leaves. If the clippings are already somewhat composted, use less leaves.
Once you get the pile balanced, keep all your extra fall leaves (mower-shredded, if convenient) in one pile. Then the next year, whenever you add clippings, stack them in another pile, spreading them an inch or two thick, and cover with the same amount of packed leaves - more if loose. Repeat, layering this up to around 3 feet, then start another pile.
If you don't have enough leaves, you may have neighbors who'd be happy to be rid of theirs.
After one of these piles has been brewing for several months, it will be time to turn it, to get more oxygen into it. Being lazy, I don't really do that. When building a pile of leaves and clippings, I also layer in partly-made compost from an adjacent pile that's been going for a while. That way I don't have to turn the other pile, and the new pile gets a lot of good composting critters.
The bottom of the adjacent pile may be ready to use long before the top. You'll want to pull this out to make room. If you've nothing else to do with it, September is a good time to top-dress the lawn with compost - up to a half-inch. It will look like heck for a couple of weeks, then be fine.
On the question of whether it's has much nitrogen, or has gone anaerobic - probably both are true. Clippings that have gone anaerobic will often turn dark green, almost black, and get slimy.
As noted earlier, splitting up the pile will make things easier, and work better.
Re smell: yes. When you make a pile with fresh clippings, and mix in the right amount of carbon (leaves), and have the right amount of moisture, the pile will get hot, turning to compost rapidly, and killing any weed seeds in the process. It may put off a smell like a cow barn, and if you stick a fork into the pile, you'll see steam come out with a strong ammonia smell. I don't know whether this will be more pervasive than the smell now. To me, it's a lot more pleasant smell, but it's a matter of er... taste.
A gardening fork is a must-have tool for compost - much easier to use than a shovel.
If you have a vegetable garden, and don't apply herbicides or pesticides to your lawn, consider using some clippings for mulch, instead of composting them. They work very well, but will bring in a few weed seeds. Don't use more than an inch or so of fresh clippings - they'll burn your plants, just like a pile of clippings in the yard will turn the grass underneath yellow. Because of the weed-seed problem, I wouldn't use clippings in a flower bed, simply because I'm not willing to spend the extra time weeding there. Your mileage may differ.