Attribute Points are ONLY awarded for Leveling.
When leveling up you get 3 attribute/skill points if your new level ends with 0 (10,20,...)
When leveling up you get 2 attribute/skill points if your new level ends with 5 (5,15,...)
When leveling up you get 1 attribute/skill points for all other levels.

So you would have a fixed amount of Attribute points!

The Skill points can be awarded for Leveling, for completing quests and achievements and collecting skyshards.
There are many more points combined. I think >300 is possible.

As stated above. After you collect 3 sky shards you are rewarded with 1 skill point. Of which you can spend in your combat or crafting skills. Sky shards are very important to look for as you will not get the skill points you need by leveling up or doing quests alone. Even more so if you are using skill points for crafting and combat at the same time. I recommend when you get to higher levels to look up sky shard locations on youtube, and watch videos that give you the location of sky shards in each region. Again they are an important thing to get.

Have a look through your skills (K for default I think) All your skills, there are a lot. That is what you use the skill points skyshards give a third towards for. They are basically just as important as your character's level, perhaps even more so. Which begs the question are all these players that try and grind to the cap missing the point about skyshards, but that is for another thread perhaps.