To encourage students to make use of alternate typefaces over the default Computer Modern ones, a new document written in Fall 2015 gives samples of 32 text fonts and 14 typewriter fonts with instructions on how to use them by adding just one or two lines to the preamble of any LaTeX document. Because character widths vary with typeface, changing the document fonts affects all line breaking and page breaking. The choice of typeface is therefore best made early in the document production process, rather than at the end, when you might otherwise have to make further tweaks to address overfull boxes, bad line breaks, suboptimal page breaks, and figure and table positioning. The complete set of files needed to make that document is available here as an InfoZIP file, and as a subdirectory of files.
For a diagram showing how page layout is specified, see Figure C.3, page 182, of The LaTeX User's Guide and Reference Manual (1994). There are more detailed diagrams here: layout.dvi, layout.pdf, layout.ps, and layout.tex.
For measuring coordinates on included graphics files, use this PDF or Encapsulated PostScript file with a numbered grid in units of PostScript points, known in TeX as big points (bp), where 72bp = 1in. Print it on a transparency on the same printer that you use for printing your graphics files, then overlay the grid on one of your pictures to measure the lower-left and upper-right (x, y) corner coordinates that are often needed to correct erroneous %%BoundingBox comments in a PostScript file, or the /MediaBox command in a PDF file. Those commands can be edited with a text editor, like those in the emacs family, that is capable of editing files with binary contents.
You can also supply the coordinates of a smaller rectangle that you wish to use as a figure, overriding the default image size by a command
\includegraphics [bb = 50 75 425 350, clip = true] {mypict}
to select the rectangle with corners at (50bp, 75bp) and (425bp, 350bp) from the image in mypict.eps or mypict.pdf, and suppress the parts of the image outside that rectangle.