Tbh, I also like to play A sol, I picked him up as my first champ cuz he looked cool, and one tip is to have your jungler gank frequently. Also, you want to contest every cs assassins try to get with your w. Look at their mana before an all in, zed can't do anything if he doesnt have any. Finally, once you get a solid lead, just roam. Just like playing against Kassadin, you do NOT want to lane against assassins when they hit power spikes, especially since it's a 1v1, and mages like A sol are more of a teamfighter, not a duelist. Assassins have to be patient in the late game, when you group, they have to wait, and that takes away their chances to all in. If you want a build, I go roa, swiftness boots, rylais, deathcap, and liandrys. then it's all situational. Hope this helps, and sorry I had to write an essay. :D