To change the default font to sans serif just type this at the beginning of your tex file:

\renewcommand{\rmdefault}{cmss}

Here are some fonts:

cmr   serif font (default)
cmss  sans serif font
cmtt  typewriter font (fixed width)
cmb   light serif font

To change the fontsize of the section headline type this at the beginning of your tex file:

\usepackage{sectsty}
\sectionfont{\LARGE}

In fact, you prepend \LARGE to the headline. You can also create italic headlines:

\sectionfont{\Huge\it }

To change the style of other headlines, just type:

\subsectionfont{\Large}
\subsubsectionfont{\Large}
\paragraphfont{\large\it}
\subparagraphfont{\normalsize\it}

You can customize header and footer with the package fancyhdr. With this package you can define 3 justified parts in headers and footers: left, center and right:

\usepackage{fancyhdr}
\pagestyle{fancy}
\rhead{\large\bfseries My LaTeX Document}  %  right header: document title
\lhead{G. Smith}                           %   left header: document author
\cfoot{\large\thepage}                     % center footer: page number

You can also define horizontal lines. Add these commands to the above:

\renewcommand{\headrulewidth}{0.4pt}
\renewcommand{\footrulewidth}{0.0pt}       % no line at footer

It is possible to create different headers and footers for equal and odd pages in a two-sided document. Use the more general command \fancyhf. To specify the parts of header and footer these selectors can be combined in the square brackets:

L - left / C - center / R - right
E - equal page / O - odd page
H - header / F - footer

Here is an example (see the result as image):

\usepackage{fancyhdr}
\pagestyle{fancy}
\renewcommand{\headrulewidth}{0.4pt}
\renewcommand{\footrulewidth}{0.0pt}
\fancyhf[ROH,LEH]{\large\bfseries My LaTeX Document}
\fancyhf[REH,LOH]{\large\nouppercase\leftmark}        % \leftmark prints the current section
\fancyhf[ROF,LEF]{\large\thepage}
\fancyhf[REF,LOF,C]{}

For more information refer to the fancyhdr Manual. On my Linux system it is located at /usr/share/texmf/doc/latex/fancyhdr/fancyhdr.dvi.

You can use \renewcommand{\labelitem... for this. Just add these lines at the beginning of your file:

\renewcommand{\labelitemi}{\fbox{I'm a bullet!}}    % this is stupid ;-)
\renewcommand{\labelitemii}{$\circ$}
\renewcommand{\labelitemiii}{$\bullet$}
\renewcommand{\labelitemiv}{$\star$}

i,ii,iii,iv specifies the depth of the item. You can use any text as label.

Sometimes the spacing between the items of the itemitze (or enumerate) environment seem to be unconvenient. This is how one can create a new itemize environment that has a parameter to control the spacing:

% new itemize environment with itemsep parameter
\newenvironment{myitemize}[1][0]
  { \begin{itemize}
    % set spacing between items
    \addtolength{\itemsep}{#1\baselineskip}
    % set spacing between lines
    \addtolength{\baselineskip}{#1\baselineskip} }
  { \end{itemize} }

See the result as image. This tip has come from here.

You can create eye-candy source listings with this package. This is a small example document:

\documentclass{article}
\usepackage{listings}
\begin{document}
  \begin{lstlisting}[language=C,numbers=left,xleftmargin=2em,stepnumber=1,frame=single]
  int main(int argc, char **argv)
  {
         return 0;
  }
  \end{lstlisting}
\end{document}

This package has many features like frames, numbers, captions and syntax highlight for a wide range of languages. I prepared a more complex example and its result as image. For more information refer to the listings Manual. On my Linux system it is located at /usr/share/texmf/doc/latex/listings/listings.dvi.

PPower4 is a post processor for pdf files to create effects useful for presentations, such as adding or removing objects, transitions and fancy backgrounds. Together with pdflatex and a hand full of TeX style file, you can create really good presentations (demo from the PPower4 homepage).
Here is a quick installation guide:

• Check if you have pdflatex and java installed.
• Download TeX style files (collected by Matt Welsh, Thanks!). Install them in $HOME/.TeX. Make sure that this path is in you $TEXINPUTS. If not, do:

  % export TEXINPUTS=$HOME/.TeX:$TEXINPUTS

• Download PPower4 (the style files, the jar package and the shell script). Install the style files in $HOME/.TeX (overwrite duplicates). Then put the pp4p.jar and ppower4 shell script into $HOME/bin. Edit the shell script to set the path to the jar file:

  jarfile=$HOME/bin/pp4p.jar

  Finally you shoud chmod 744 the the shell script.

That's all! Now you can test your setup. To create an example presentation, do:

% wget http://www.ctan.org/tex-archive/support/ppower4/examplee.zip
% unzip examplee.zip 
% pdflatex exm2.tex
[lots of output]
% ppower4 exm2.pdf result.pdf
[some output]
% xpdf result.pdf

For more help, examples and manuals refer to these websites:

• PPower4 homepage
• Installation guide from Matt Welsh