There are three ways you can win the game:
1. By final combat
2. By sealing gates
3. By closing gates
Some Ancient Ones are easier to defeat in final combat, and some are easier to defeat by sealing gates.
If you're aiming at winning the game by final combat, prepare for whatever it says on the Ancient One sheet. And try to bless all your investigators and collect (the right) spells, common items, unique items, allies and skills. Also, clue tokens can be very useful in the final combat. Clue tokens give you extra dice to roll in a check, not the ability re-roll failed dice. So, if all your dice are successes, you can add more dice, and thus have the opportunity to roll more successes, by spending clue tokens.
If you're aiming at winning the game by sealing gates, collecting clues and sealing the gates is paramount. You need to distribute the clue tokens so that the investigators which are to seal gates have enough clue tokens. Clue tokens are a limited resource, so spend them wisely. Also, clue tokens in a location disappear when gates open, so make it high priority to visit a location if there are several clue tokens there. Not all locations have equal probability of a gate opening. If gates open at Independence Square, Unvisited Isle, The Witch House or Woods these gates should have higher priority. If you're not able to seal a gate in one of these locations rightaway, it may be better to leave the gate open until you are able to seal it. If another gate opens in the same location, the result will be a monster surge, in which case you don't add a doom token to the doom track.
Victory by closing gates doesn't happen too often, and it doesn't depend much on the Ancient One. It's mostly an opportunity which presents itself now and then, depending, among other things, on where and when gates open.
If you wish to win by sealing gates, playing more investigators should help. I usually play four investigators, and I have no trouble winning. But your goal during a single game may change, though. If you try to win by sealing gates, and realize it's not going to happen, you should start preparing for the final combat.
There's a lot more that can be said, but this should cover the basics. You'll learn a lot just by playing the game a few times.
When the game starts, look at the starting resources. Focus on clues: investigators with the most starting clues are those who are asked to gather other clues as soon as possible: after the initial Mythos card (the so called "Mythos Zero"), there must be two clues on some location of the board. Send there the investigators with most clues, so that hopefully he can have the 5 clues very soon.
…unless you're playing with Innsmouth. =P (or possibly some other expansion) Evidence Destroyed! is always a great way to start a game. No clues plus a gate at Y'ha-nthlei. ^__^
Judgement Dave said:
I'd assumed they were probably equal and it was just pure luck having many gates in one location on two of my four games (as described above). I'm a litle disappointed to hear that some locations aren't hit much.
Do any of the expansions (official or unofficial) help even out the spawns for base game locations?
Adding small box expansions will slightly reduce the probability of gates spawning at high tier locations (Independence Square, Unvisited Isle, The Witch House or Woods), and will slightly increase the probability of gates spawning at low tier locations (Hibb's Roadhouse, Historical Society, Science Building or Silver Twilight Lodge). Adding more small box expansions will increase the effect, but the probability of a gate spawning in a high tier location will still be much higher than that of a low tier location. Adding the Innsmouth and/or Dunwich expansion board will increase the number of unstable locations, and reduce the probability of a gate opening in a sealed location. If you want to do the math, you can check out this list.