Following notes are reproduced from here

Typesetting

Grace permits quite complex typesetting on a per string basis. Any
string displayed (titles, legends, tick marks,...) may contain special
control codes to display subscripts, change fonts within the string
etc.

Example:

F\sX\N(\xe\f{}) = sin(\xe\f{})\#{b7}e\S-X\N\#{b7}cos(\xe\f{}) 

Control code Description
\f{x} switch to font named "x", e.g. \f{Times}
\f{n} switch to font number n
\f{}  return to original font
\R{x} switch to color named "x"
\R{n} switch to color number n
\R{}  return to original color
\#{x} treat "x" (must be of even length) as list of hexadecimal char
codes
\t{xx xy yx yy}apply transformation matrix
\t{}  reset transformation matrix
\z{x} zoom x times
\z{}  return to original zoom
\r{x} rotate by x degrees
\l{x} slant by factor x
\v{x} shift vertically by x
\v{}  return to unshifted baseline
\V{x} shift baseline by x
\V{}  reset baseline
\h{x} horizontal shift by x
\n new line
\u begin underline
\U stop underline
\o begin overline
\O stop overline
\Fk enable kerning
\FK disable kerning
\Fl enable ligatures
\FL disable ligatures
\m{n} mark current position as n
\M{n} return to saved position n
\dl LtoR substring direction
\dr RtoL substring direction
\dL LtoR text advancing
\dR RtoL text advancing
\x  switch to Symbol font (same as \f{Symbol})
\+  increase size (same as \z{1.19} ; 1.19 = sqrt(sqrt(2)))
\-  decrease size (same as \z{0.84} ; 0.84 = 1/sqrt(sqrt(2)))
\s  begin subscripting (same as \v{-0.4}\z{0.71})
\S  begin superscripting (same as \v{0.6}\z{0.71})
\T{xx xy yx yy}	same as \t{}\t{xx xy yx yy}
\Z{x} absolute zoom x times (same as \z{}\z{x})
\q make font oblique (same as \l{0.25})
\Q undo oblique (same as \l{-0.25})
\N return to normal style (same as \v{}\t{})
\\ print \
\n switch to font number n (0-9) (deprecated)
\c begin using upper 128 characters of set (deprecated)
\C stop using upper 128 characters of set (deprecated) 

Putting Symbols into Axis labels:

If you need special characters or special formatting in your label,
you can use grace escape sequences (the sequence will appear verbatim
in the text field but will be rendered on the graph), see typesetting
above. If you don't remember the mapping between alphabetic characters
and the glyph you need in some specific fonts (mainly symbol and
zapfdingbats), you can invoke the font tool from the text field by
hitting CTRL-e. You can change fonts and select characters from there,
they will be copied back in the text field when you press the "Accept"
button. Beware of the position of the cursor as you enter text or
change font in the font tool, the character or command will be
inserted at this position, not at the end of the string!

Note that you should see \f{Symbol} in the Cstring field of font tool
when you select a symbol. In case you don't, write down manually and
then click on a symbol you wish to insert and then press 'Accept'.

overlaying graphs

   1. Begin by selecting Main:Edit/Overlay graphs to bring up the
   Overlay widget.
   2. Select the graph numbers with which we would like to deal. In
   this example, we will overlay graph 1 onto graph 0. At this point,
   only graph 0 is visible. We cannot see Graph 1 to select since it
   does not exist at this point. We need to create simply by pressing
   mouse button 3 in a graph list window and selecting create new.
   3. The overlay type is determined by what is common among the
   overlayed graphs. In our example, the x axis is common so we will
   select X-axes same, Y-axes different. This is important because we
   don't want to alter any axes of the Overlay graph which we set the
   same as the underlay graph. In this example, we don't want to alter
   the x-axis of graph 1.
   4. We are now ready to label the graph axes and read the data. One
   thing we must be careful to do is to always make sure that we are
   working on the intended graph. Seeing as the graphs are overlain,
   clicking within the frame is ambiguous as to what graph is
   selected. The rule is that in a region of overlay, clicking will
   cycle between the graphs. Hence, if graph 1 is selecting, clicking
   within the frame will toggle to graph 0.
   5. Making sure that graph 0 is active, bring up the Axis properties
   widget. Now set the y axis title to Gnus.
   6. Select graph 1 as active as set the title as Gnats. Notice how
   it overlaps the Gnus. We want to put this on the right side. From
   the axis label and bar tab, select label Properties/Side=Opposite.
   7. Label the x axis to label it. If graph 1 is the current graph,
   noticed how it is greyed out because only 1 x axis need be
   active. Select graph 0 and you should now be able to alter the axis
   label.
   8. You are ready to read in data. Just make sure the graph that is
   active when you read in the data (or create your set) is the one in
   which you intend it to go.