There are several possibilities for controlling float placement. The question I see most here is along the lines of "How do I insert an image/table at the point I list it in the source document?".
First I think it is important to note that you don't need to use floats. An includegraphics does not need a surrounding figure and a tabular does not need a surrounding table. If captions are required, the \captionof command from the caption package can be used (perhaps they need to be boxed up to prevent a pagebreak between content and caption).
If a float environment is required, but the "amount of float" has to be limited to keep the content relatively close to the point where it was defined in the source, then the \FloatBarrier command from the placeins package can be used. This command specifies a barrier beyond which floats may not pass.