The max for attributes that you can assign is 15, you can get it higher by equipment.
The max for abilities that you can assign is 5, you can get it higher by equipment. Some skills like crafting and blacksmithing do not benefit from being over 5, so you can rely on equipment getting you to max to save points.
There are other things important for planning but I don't know how much you care about spoilers. If you don't care, let me know and I'll tell you the rest.
