\label{} for internal referencing, e.g. Figure and Table numbering.

\label{fig:Lname2000_Fig7b} "fig" is a user-set class.  I also use "tbl" for tables.  "Lname2000_Fig7b" is user set too, but I recommend you adopt a naming algorithm that makes labels and citations easy to remember.

\label MUST be on the line immediately following \caption to work. 

\captionof{element}{Caption text.} vs \caption{Caption text.}

\captionof{figure}{Caption text.} vs \caption{Caption text.} ... _NEED REF_ These have different purposes/effects. 
\captionof{table} or other elements work in this manner.

The Lazy Mathematician's blog covering drawing, lists, graphs, plots, functions, and page layout.

The Lazy Mathematician's blog.

I haven't delved into this yet, but I'm keeping it for later reference.