few questions about twitter?

[CJC]

So i have had my twitter account for 2-3 days but am still confused about quite a few things,
1: how do people see your tweets if they are not following you, because I can only see the tweets of the people i'm following... I know that if you use the # or @ people can search for that topic and then see the tweet but what if you don't use the # or the @ in the post how do people find it then? Because earlier I tweeted something with no # or @ and someone replied within minutes.
2: how can I find interesting people to follow... so far I only follow famous people/businesses etc and the few people who have followed me
3:how can I get a decent ammount of people to follow me.. i'm not someone who wants 100's of random followers just for the sake of it... but i would like quite a few, preferably with similar interests

I think that's all for the moment and thanks in advance