Welcome to Guild Wars and welcome to Guild Wars Guru. (The other sites aren't as in depth so you picked the best.)
A new Ranger would have difficulty in today's meta in hard mode, but any class should be able to do normal mode.
A key thing to remember as a Ranger is that d-shot (distracting shot, in expertise) should more or less be stapled to your skillbar.
R/Mo would probably be viable only for mending touch with a maximum of 3 specced in protection prayers. You want to pump expertise and marksmanship.
Touch skills like Vampiric Touch, Mending touch, and Blackout are reduced by Expertise. They are of limited use in PvE (i.e. anything not Player versus Player).
Key Ranger tips:
Use a recurve bow unless you are running Barrage, which is when you want to run a Flatbow
Recurve has lowest flight time, which means it has the shortest time for the arrow to hit
Sloth Hunter's Shot does damage, but that's about the only skill that does high damage (50ish + base damage from bow) compared to other classes. Rangers are designed to be survivable.
+damage from attack skills is armor ignoring. This is why power shot is lame, since you only do the listed damage, never more.
Pets have terrible AI when it comes to aggro
Don't use an elemental damage weapon (fiery, icy, shocking, ebon) when partied with a Necromancer. They might be half decent and run Barbs.
Traps aren't worth bringing unless you devote bar to them (i.e. Trapper's Focus). Even then, they are bad.
Barrage is adjacent range. It doesn't work with preparations also.
Don't use your secondary as your primary (especially spellcaster stuff like elementalist spells).
Don't use /Mo as a secondary for the point of healing people. It's a bad idea. You have 3 energy regeneration and no Divine Favor.
EDIT: Check
http://wiki.guildwars.com/wiki/Guide...ng_as_a_ranger
and
http://www.gwpvx.com/Guide:Ranger