Just look for ammonia that's pure ammonia, no dyes, scents/fragrances/perfumes, and no surfactants.
If you're not sure, you can shake the bottle - if there is noticeable sudsing, don't use it.
I've heard of people throwing in bits of raw shrimp, but that's a little more difficult since you don't really have any ability to control the amount of ammonia going into the tank.
I've also heard of people cycling with fish food, by trying to estimate how much they would add to feed there fish. I imagine that would probably work, but it will also probably make a mess of your tank in the process. Also, I don't think this or the shrimp method would work very well if you have snails in your tank.
There have even been a couple people who have used urine...
anyways, if you have a large enough biomass of fast-growing plants and a small fish load, it's quite possible that the plants will take up all the ammonia as it's produced by the fish, and just shortcut the whole cycling process.
Even if you don't have enough to completely skip the cycle, they will help some. Floaters and emmersed plants especially so.
here's a link to one of Diana's posts:
I really think her guide should be added to the FAQs/stickies, it's pretty thorough.
Anyways, as to the first day, I'd get it all set up, planted, filled with water (maybe changed out if there's an issue with suspended sediment), and draw a bit of water for testing later.
Then add whatever you are using as your ammonia source. If it's straight ammonia, it should be relatively easy to add some to a bucket or something of a known size, and test that to get an idea of how much ammonia solution to add to raise your tank 1ppm.
if it's food, shrimp, urine, etc., I'd try and do several ammonia tests through out the next couple days, to try and get an idea of how much ammonia is getting released, and how fast/long, and try and use that to make estimates of how much and when to add more food/shrimp/urine/etc.
I haven't tried this method, so I don't know how well it would work, but if I were to try it, that's probably how I would approach it.
Once you get your ammonia dosing sorted out, keep doing a water test everyday, and keep an eye out for NO2. The bacteria that convert NO2 are a bit slower to get established, so most of your cycle will probably waiting for those bacteria to grow in.
After that, you can keep dosing the ammonia source until you add your fish, just do a pretty big water change before adding fish to get the NO3 down to a reasonable level.
Using Diana's cycling guide will get you a pretty big population of bacteria, that can handle a pretty densely stocked tank.