How to align form fields?

I want to align my form fields into two columns.

I have several different kinds of fileds - text, date, radio button, dropdown etc.

When I shrink them, and try to align them in two columns, they never align.  Why are the fields not automatically sized to the width of the column and fit into the column.

For example, the Name field and Date of Birth field (date) never easily fit into one row easily.

What am I missing?

No - not really.  I had to spend hours to get them to line up just so.

I will have fields for each participant in the form - eg name and dob etc.

For each participant I want these to be organized the same way.  As soon as I add a field, everything moves around and takes a long time to rearrange.  Is there a better way to do this?  

Why don't the fields resize to the column size - they seem to but they don't.  Is there a way to fine tune the field size?