Hello dear fellow RO player,
It is great to hear you have an invested interest in playing the two mage line classes, and there is no greater joy for everyone than to teach you the ropes.
Below I outline some of the main perks of the "for fun" pvm builds to get you to max level before you decide what actual role you want the Warlock and Sorcerer to play (do take time to read about what skills do on irowiki, below is just a very fast quick rundown to start you):
This is a very basic bread and butter pvm build made to get you to max level as fast as possible. Skill points remain in all 3 jobs, place them as you see fit.
Important from the 2nd class stage is using Indulge to recover SP at the cost of HP, free cast to allow some minimal movement while casting spells, Dispell is both useful in WoE and PvM/MvP, removes most buffs off a target,
As a Sorcerer, unless you have alot of cooldown reduction gears for your skills (OCP gears mostly), just cycle using the 4 main big AoE skills, psychic wave-diamond dust-varetyr spear-earth grave, the original definitive combo of sorcerers. You also have access to summoning all spirits, different levels will allow passive buffs to certain skills or effects.
Probably the harder of the two classes to gear up and figure out how you want to play. Make no mistake, Warlock has greater damage potential than a Sorcerer, but does require an equivalent amount of gear investment to produce results. Same as Sorcerer skill build, this ones made for you to PvM to success before you figure out what you want to build your Warlock around.
As with the Sorcerer build, I left you many skill points to mix and match to your liking, there is no real way to build the skill as it all highly depends what endgame gear combination you want, notably from the 2nd job I left you at max level Soul Drain and max level Mystical Amp, these are the trumps of the wizard line and is what separates the wizards from the sages, Soul Drain to recover SP when you kill monsters with targeted spells, and mystical Amp to give you the boost to your next spell, meaning the need to reach max INT is not as imperative as with Sorcerer, more breathing room to get the rest of your stats before maxing out your INT for damage. Storm gust is probably the most retarded spell that does everything you want, stop targets via frozen and does a good chunk of damage, good to use as a h/wiz but you will drop off later possibly. Gravitional Field is your definitive best, hands down Neutral AoE elemental skill aside from the warlocks Comet skill.
With Warlock comes the big boy AOE skills, Crimson Rock and Soul Expansion(aka white doritos) are the bread and butter skills, with Jackfrost to frozen targets and chain lightning for some fun. You can't get anything wrong here, this is possibly the fastest way to reach max level. Drain life to help recover HP from a single target, and recognised spell to help your spells reach the highest variance in damage.
These are just the basic of the most basics for you to start off as with playing these two classes. People will probably tell you they have other opinions than what I have presented to you, and that's okay, these two classes have so many ways you can play it, no playstyle can be said to be the single best.