Broadly speaking there are 2 different types of mortgage; repayment and interest only. The efficacy of the two depends entirely on your financial circumstances.

Is it okay if I take pictures on a viewing?

This is actually a very good idea, and should not be a problem, but for the sake of etiquette ask the seller's permission before snapping away.

How important is it to know the state of the property market?

This information could prove very useful. For example, if it is a buyers market you could get away with offering less for the property than you first anticipated.

Is a verbal offer legally binding?

In Scotland it is, but not in England and Wales.

Do I have to pay stamp duty?

Not necessarily. Certain areas are designated by the government as 'disadvantaged'. Any property purchase of £150,000 or less in such an area will not require the payment of stamp duty.

Should I get surveys done on the property?

If you have any suspicions about a property you are interested in, or if you just want some peace of mind before purchase, then a survey is a good idea.