Right now i have one follower, Lydia. How should i start building an army out of npcs from quests? Which quests should i get and where do i get them? Is there any way to get more than 1 follower?

You may only have one follower at a time unless your followers conjure something to fight with you but that is limited. Look on skyrim wiki they have a great list of all available npcs for companions and the quest or requirements to recruit them. Link is here http://elderscrolls.wikia.com/wiki/Category:Skyrim:_Followers

You should get learn to have two summons at a time. And you should have J'Zargo as a follower, as he also summons daedra to help out. That means you can have a party of 5. I think you might be able to stick a dog into that as well, but I'm not sure.

There HAS to be some multiple follower glitches.

You could only have one in FO3 and I had five or six.

It can be fun to raise a small army once your leveled out.

You could have two in Fallout 3, not including the dog - with Dogmeat that makes three!

does J'Zargo use thrall spells to have whatever summon with him forever? that would make it much more fun and you can fit a dog in there too

Where do i find JZargo? Is he related to a mission? Amy other people that arnt related to missions that i can easily pickup?

I'm sure there's a mod to take out the follower limit, assuming you're on the PC.