For a pre specialization mage you can try something like this:
Energy Barrage - All around great single target damage.
Winter's Grasp - Another single target damage spell with some cc attached.
Immolate + Consuming Fire upgrade - Great aoe +dot and upgrade makes it spammable (sort of)
Flashpoint - After a crit, it makes next spell not trigger its cooldown.
Barrier - Provides mitigation for the party.
Peaceful Aura - Keeps mob attention on tanks and not you.
Dispel - Useful for dealing with enemy Barrier spells but more importantly instantly kills 2nd wave demons from rifts if you cast it on the spot the visuals indicate they are going to spawn from. This is especially useful in early rift battles when your party has low end gear and limited skills to use.
Rejuvenating Barrier - This passive makes your Barrier spell also buff mana and stamina regen.
All these skills total 9 points. You start with 2 and gain 1 every level thereafter (barring any amulets) so you can have all these skills by level 8. The thing to remember with low level characters is that cooldowns and resource management (mana/stamina) are the primary limiters to your combat ability. Deal with those and everything else falls in to place. This skill selection I laid out address those two issues as best as possible pre-Skyhold/pre-specializations. Obviously things change once you have access to specializations and more skill points. While Flashpoint won't have as huge an impact at low levels, you can use crafted gear to help shore up your crit chance early on making it's impact more noticeable.