True AP value not visible due to builder not working ap gain from Galio's passive.

Use the boots to keep your distance, and harass with spells.

Carry on till you have about 1000g (about lvl 3 or 4) and go buy the challace to increase your harassment abilities.

As you approach mid lvl 5 start playing more def near your tower (if your not getting gank help from jungler) and use your ulti when you reach lvl 6 to draw them into turret fire and right time. (Use shield to increase your ap and endurance).

By the time you have Merc, Challace and Nature you should have about 92ap, and be doing some serious damage, whilst owning any ap tanking. If enemy team's carry is doing too much damage against you after getting thornmail, opt for sunfire cape over deathcap.