Here is the best advice on shaman build in Requiem, as level (requiem gold) 41 Shaman. You may choose to build yours differently based on how you would like to customize your character, which is as it should be, but here is how we rolled mine.
If you choose to build your character as we did, then your primary attack skills would be: Fireball level (requiem lant) 5. This is the first skill you can take and it is the best one you've got. With only a 0.6 sec cool down time, FB spammage is clearly at hand. Use it, don't regret it, use it and use it often. In between cool downs you will have the chance to take a swing at the mob, so do it, but only one swing, then back to another fireball, swing, fireball, swing. Better yet, alternate FB, Fire Arrow, FB, Soul Expl, FB for
Fire Totem level 5. An outstanding skill offering serious damage output. And you get it fairly early on. At level 5 it does 330 DMG per target, up to 8 targets, with an additional base continuous DMG of 13/2 per target of burning damage for 10 secs. The first DOT of fire totem, the 330 DMG, is not modified by INT. The second part, the continous burning DMG, increases as your INT increases, as is true with fireball, most spells in general, and all elemental. Since DNA cannot be used to increase DOT aspects of Shaman skills, this is another reason why INT is so important for increasing your damage per second.