There's so much to this question and- IMO- the worst answer is the "I have a ______ and it works great" because a pile of those implies that there is one best choice.
The antennaweb suggestion is definitely a great place to start as it will reveal several important things like relevance (your area, direct lines to towers or mountains/obstacles, all the towers generally in one direction or towers all around, etc). Stuff that like plays a BIG role in selecting the best antenna for any person.
Higher the better is generally universally true. Bigger the better also tends to be true much of the time (meaning, if antennaweb suggests a size for your location, you shouldn't assume that the next size up is "bad"; in other words, antennaweb is answering a question that is not about "best" but about "minimal size" akin to a Mac built in about 2002 being good enough for the bulk of someone's uses but that doesn't automatically mean you should only consider buying a Mac from 2002).
If you happen to be in a house that has an old antenna already up there, hook it up as a test. It will probably work just as good as any new antenna you might buy (and is probably already optimized for direction to the towers, etc). "HD" and "Digital" antennas are generally marketing spin vs. "analog" antennas that are already in place on many houses. Sometimes, the old ones are BETTER than the new, more cheaply made ones.
As very general answer:
1) consult antennaweb,
2) shift up a size from their recommendation (go a little bigger than they say) for a little added insurance,
3) unless you must, don't subjectively pick the spot for the antenna but get up there and try different locations (even a few feet can make a difference),
4) higher the better,
5) if your towers are all around you, a remote-controlled rotor can be HUGE,
6) if your towers are far away, a signal booster can help but don't assume max boost is the best (signal boosters boost both good and bad, so a max booster will boost good & bad to the max; there is a concept of signal overload which can be just as bad as receiving too little signal),
7) this is one of those things where the difference in price between finest quality and cheapest quality might be $200 at worst AND it's one of those things that once it's up there, you probably use it for 10-20 years. As such- IMO- letting price dominate your decision seems like the wrong way to go at a pursuit of high quality. For instance, if you spend $200 on what appears to be the ideal antenna per all of the above, $200/15 years = the equivalent of about $13 per year. Short answer: get the good one.
8) Chasing extra signals about 65-75+ miles away is like fools gold- they'll sometimes come in solidly but other times be impossible to find. One can get consumed in trying to break the laws of physics by tweaking these, endlessly chasing the extra channels too distant to be reliably locked. Exception: if you are on a mountain top with clear line of sight to towers even 100+ miles away, you may be surprised at the reach. Otherwise, don't be seduced into thinking you're in a very special situation where the laws of physics are bent in your favor. There may be a few such places in the world but the odds are against you; it's much more likely that very distant signal locks are driven by #9…
9) Don't gauge signal strength on a very cloudy day. Signals bounce off clouds and in some circumstances you can pick up television signals from hundreds of miles away for a while (until the clouds move/dissipate). 9B) And Nighttime signal strength seems to be superior to daytime signal strength so do your install and testing in the latter. If you test in the evening/night, you might lock on a few channels that are lost during the day.
10) If you live in a HOA situation, be sure to search for OTARD (nutshell, HOAs are not GOD; the owner of a home has every right to receive television signals over the air via an outdoor antenna). HOAs will bluff to no end but the homeowner has the FCC with them on this matter (superseding any overbearing HOA rules/requirements).
11) don't install on a high-wind, snowy/icy or thunderstorm day,
12) metal antenna that touches house electric lines will yield a bad hair day just for starters,
13) if you reject #11 or #12, be sure to have lots of life insurance.
And one more thing: Plan for the unexpected, meaning run an extra cable or two up there that you tie off just in case you might need a companion antenna in the future. And use highest quality cable for these runs (again #7 applies to the supporting pieces like the cables where the difference between best & worst might be $20… and also get used for 10-20 years (that's $1-$2/yr).
