New to the Game

I would say the only reason you should make more than one character is for more meseta income. I wouldn't advise having additional characters with intention of maining other class roles as this would mean you'd also have to be gearing them in addition to your main character (you can if you want, but it's more effort involved obviously), it can also cause problems if you want to switch character at EQ times because you risk being locked out of populated blocks.

Additional characters are useful for earning more meseta as it would allow you to do DQ's & TACO's on all 3.

You can't freely reset your skills but Sega does give out skill resets every now and then - I'm not sure how often but I have around 30 of them saved up since I started playing 4 years ago.

If you do end up enjoying this game and want to min/max class roles, I'd recommend spending a bit of real money on AC to unlock additional skill sheets - this isn't too necessary for some classes, but for something like FO/TE it can be difficult to do decent damage if you aren't able to switch between element specs.

I personally haven't bought any additional skill sheets because I'm not too bothered about doing average damage for some classes, other classes don't require more than one spec.

Though I have bought 2 additional mags so I have one each for SATK/RATK/TATK and I would recommend doing this if you'd prefer to stick to gearing just 1 character because it's a pretty cheap investment.

As for prem - I feel the only useful benefits are being able to access full blocks and ability to buy 12* stuff from playershops.

You can get player shop passes for free using FUN points which will allow you to sell stuff in addition to buying so I wouldn't get prem just for that. There's also a few titles that let you buy a few 12* weapons from player shops so you may not need prem for that either.

Skill build depends on which classes you're interested in playing.

This may help a bit: http://imgur.com/a/8l7TD#0 It's 2 years old though so I'm not sure if it's still relevant and I haven't been able to login for a few months so I'm not sure about any new changes.

You can find discussion on classes here too: http://www.pso-world.com/forums/forumdisplay.php?f=45

/r/PSO2 Thread