Pausing a game

Hey guys, I'm brand new to AoE2 (well I played it a ton when I was a kid and just recently rediscovered it and was amazed there's a community, online games, etc.)... I have a few questions...

1. My childhood best friend and I tried to play a game last night against AI and I needed to pause it for a few minutes and couldn't figure out how to pause the entire game. Is there a way? We were only playing AI so I thought I should be able to do that. Can you pause games when you're playing humans, too?
2. There's a ton of strategies that I had no clue on growing up. I never attacked early, tower or knight rushed. So I'm learning a lot. But one thing I'm still struggling with is micro'ing. How did you guys learn to micro? Watching videos and practicing? I've experimented with onagers and archers but so far its been ugly
3. Why do so many lobby games have maps already explored? isn't that cheating? why is that so popular?