So ur items are for an AOS map right? So here is some tips for u:
1/ Create items that will suitable for all heroes. (Some will help in the beginning, other in the late game). The beginning items should give the heroes some stat, some damage or some regen.
2/ Create items for heroes in each classes to suit what they do best. For example:
+Tanker Hero (These heroeswill take all damage for the team) need strength, armor, magic regist, HP regen, etc...
+Damage Dealer (these heroes will deal huge amount of physical damage (Sometimes magic damage as an orb effect ability) to the enemy) need attack speed, damage, some passive ability like slow attack, armor reduction, evasion, bass, critical strike, etc
+Supporter (these heroes will have ability to help ur team such as buff, healing skill or aura) need not too expensive item but must be effective. They need something to keep them alive in the combat or something that will make their support role more effective (aura may be).
Those are some tips that I can give u.