20mm - choosing the right aperture

A pretty basic and fundamental concept to most of you I'm sure, however, as I've just joined the MicoFourThirds scene from a P&S, it's an element of control that I'm not used to specifying.

The question is with specific reference to the 20mm f1.7, in case it has any peculiar characteristics.

So how do you ensure you've chosen the best aperture for the type of shot you're after?

To achieve a shallow DoF, I understand I should be shooting at f1.7, and that getting closer to my subject will help create the effect.

However, what about when wanting everything in the frame in focus?

I've found that it's not simply a case of jumping up towards f12-16 - because when I do this, well it seems like I need a tripod because the output is slightly blurry. Should once expect to take perfectly clear shots at f12-16 ?

How would one ensure everything is in focus, without using a tripod?