How do I ensure that figures appear in the section they're associated with?

Question

Often floats may land quite a bit later in the document than the point they are created, sometimes after a section break.

Is there a way to force a new section to start on a new page, after any unplaced floats?

Answer 1

Use the placeins package.

It gives you a \FloatBarrier command that you can use to prevent floats to appear beyond some point in your document. Use it as

% ... some floats here ...

\FloatBarrier
\section{My new section} % will not include floats from previous sections

Answer 2

The command \clearpage will not only start a new page, but will also force any unset floats to be set before the page break. For documents with a left and a right page, \cleardoublepage does the same, but also ensures that the next non-blank page is a right hand page.

This is all independent of the section break, save that if you are using a class that does not put a page break before section breaks, this method will force them. But, from your question, this doesn't seem to be a problem in your case.