Going into debt & the market questions?

Hey all, I've heard about gearing a home loan for a IP and be able to claim the interest on tax.
So my 1st question is..
Is it financially smart to go out and get a loan to purchase a couple of smallish IP's, say totalling $1 million +? Assuming you get accepted for a $1,000,000 loan in the 1st place?

I'd assume you'd have to have a well paying job in the case of bad tennants, and if you have no tenants for a period to be able to meet the loan repayments.

And the 2nd,
I always here people talking about "the market" when IP's come into question.
So what exactly is the market? What influences it?, how do I find out how the market is doing? And how do you work with the market?

From what I understand, the market influences price of the IP and you buy when the market is low and sell when high?