Well, if you plan to use the priest side strictly as a second class and you don't mind levelling it with dailies, just max the general skills on your priest and forget the class-specific ones. You will be using regenerate and urgent heal iirc, and also holy aura (no tp there). Rising tide you may as well max as well, you'll be using it on your priest and it will convert to an instant cast on your mage (that's an elite, level 40ish or so)
As far as the mage side goes, that will depend on your playstyle, and now is the time to throw points in stuff willy-nilly and try them out.
Flame is your bread-and-butter skill, I always maxed that first. Fireball I did next, then your passive wind and fire masteries. Those cap at 50, so just do them as you go. Buff-wise, Essence of Magic is a great skill, as is Intensification and Energy Influx (after level 65 they become amazing, you can skip them for now).
Which dps skills you level will depend on what you like. Flame and Fireball are givens, but some people like Phoenix and Meteor Shower, and I have them both at 0 and not on my hotbar. I leveled Purgatory Fire and Thunderstorm because I love those and use them all the time. I am starting to put some tp in Plasma Arrow, not for the dps, but for the crit buff you get after you use it. Some mages actually use Electric Bolt for damage, I don't. Just on gates in siege war.
Then you have crowd control. Silence is great, level that for PvP and also for use on bosses. Works great on Ancalon in Forsaken Abbey, give it a try. Lightning is great in PvP and on mobs, but you don't have to level it too high, cause it roots the same no matter the level if i recall correctly. Some people like to level Discharge, but that only increases the damage it does, and not the length of the stun, so I left mine at 0 even though I use it all the time.
Just play around for now and see what you like. But you can be confident that M/P is a good high-dps utility mage at endgame. It's not the top dps mage, but it can hold it's own. It's easy and fun to play, and if you get bored you can always pick up a third class and swap in between them.
Fandreith
GL, Notorious, Palenque
