Well I'm no expert, but my mom thinks I am.
Things I noticed in this thread so far...
1. wort chiller. You know you want one, we know you're probably about to get one.
2. bottling day... do you have a bottling wand? they work wonders and I can't see how anyone could bottle without one (unless they have that fancy bottling gun
thingie, but the wand is fine).
3. fermentation on my beers is usually begun within 24 hours and mostly stopped after 72, so this is normal. I generally make ales in the 1.050-1.065 OG range, so this might not apply if you do something heavier.
4. get a gram scale and weigh
your sugar. I got one from amazon, I think it was about 12 bucks. Since doing it this way, I've been right where I want to be carbonation wise almost every time.
5. I personally fill each bottle till it just barely reaches the top or overflows slightly, then remove bottling wand. this gives the right amount of headspace every time. I cap every bottle immediately, but I don't know that this is a major issue for you.
6. obviously you need more heat so you can get a full rolling boil.
7. I would just skip the secondary. Unless you're doing something big like a RIS or barleywine, these kit beers and extract ales of average strength just don't need a secondary. I would recommend at least two weeks on primary, but still skip the secondary.
8. no need for secondary for dry hopping either. For clarity, you can use a sanitized nylon paint strainer bag weighed down with something stainless steel, or some marbles. Make sure everything is sanitized (except the hops, which won't hurt the beer). I often toss the dry hops in anywhere from 3-7 days before I plan to bottle. Any comments on optimal dry hopping anyone? This always works well for me though.
9. Clarity is over-rated. However, you can get pretty good clarity by using paint strainer bags for the hops (in boil, dry hopping), using a sanitized paint strainer bag over the end of your auto-siphon when you rack to the bottling bucket, and by using Irish moss. I toss in some Irish moss to every boil too (about a quarter tsp). The tub isn't that expensive and it lasts forever because you don't use much.
10. I honestly don't think that brewing your kit three weeks earlier would have made any difference at all unless you just had horrid storage conditions.