What is the best method to choose whom to lynch on the first day?
The first day it is awfully random.  However, there are a few rules of thumb you can use.

First, you mentioned the seer, so let's get that out of the way, then the rest of my explanation should work for games without seers.

As a seer you should stay quiet until you've identified a werewolf.  Once you've identified a werewolf:


Say "I am a seer"
Reveal who've you've identified good and bad
The other seers in the game should ALSO admit to being seers, and give the information they've learned


Once this is done, there may be a werewolf masquerading as a seer.  This is fine, as both groups now will kill each other off until there are no more people claiming to be seers.  Since cards are revealed, you now know which seer information to trust and which not to trust.

Next, assume a game with no (more) seers.

To figure out who and how to accuse, consider the following:

As a werewolf:


The odds are against you, accuse the more experienced player
If you feel like the group is a forgiving one, accuse your other werewolf, be antagonistic to him throughout the game.  If this is known it's likely you'll be seen as safe once one of you dies.
Say nothing, at all, ever.  People tend to accuse people seen to have 'agendas'


As a human:


Accuse the most experienced player.  He is the one most likely to succeed at deception.
Accuse the most impatient person.  A werewolf doesn't need to wonder anything.  Wondering takes cognitive cycles, so werewolves tend to be quicker to talk/accuse.
With a 2/8 split, your odds of choosing someone randomly as a villager are 5:2 (71%).  So have all the players, simultaneously, choose a person at random and point to that person.  This is their 'safe' person that they'll 'trust' throughout the game.  If any two people are pointing to each other (the odds are against this), kill that person, else kill the person with the fewest fingers pointing at him.  (NOTE: The two at each other prevents the werewolves from protecting themselves).    Do not change your safe person throughout the game.  If your safe person dies, you do NOT choose a new one.   This technique works not within a single game (the odds of who gets the most safe fingers is random), but across games, as this makes the safer people MORE OFTEN the villagers than the werewolves.  The 'no two at each other rule' also helps to make the werewolves less likely to have the most votes. 


BTW, cold-reading, is a perfectly valid strategy.  I correctly identified, on the very first round, a werewolf in 9 of my last 10 games I played.  The biggest tell is a change in people's behavior.  Most people are not good actors and can't help but play differently.