What are the actual differences between the two? I am new to LaTeX and I need to create a custom "look & feel" -- should I be looking into making a class or a style?
To answer your question directly: imho, you should start by seeing if you can tweak one of the ready-made
documentclass, and if you really can't get it to look the way you want (which is really quite unlikely), then consider making your own (but I don't think anyone would recommend this until you've experimented extensively with the choices described below).
articleis one of the most simple, and will allow the highest section level as
bookare the next ones up from
articleand will make the highest section level as
In each of these classes, you will likely use packages to help you tweak the appearance such as
geometryto get your page dimensions setup
fancyhdrto get your headers and footers
enumitemto customize your enumerations
titlesecto customize your section/chapter headings
tufte-book class has some particularly aesthetically pleasing settings by default.
Once you are familiar with these classes, you can move on to some of the more intricate classes such as
koma-script, etc. I describe these as intricate because some of the packages that work with the 'basic' classes do not work with these (they have their own way of doing the same thing).
Once you've produced a few simple documents and you want to put some 'bling' into them, you could start by reading the following post, and the answers within:
In modern LaTeX a class is one of the major formats for documents. It is invoked using
\documentclass. Style files sit on top of these, and are invoked using
\usepackage. If you absolutely have to make something, then make an example document using a standard class first, then use some
newcommands and other tweaks to get it looking how you like, and then bundle those bits of your preamble into a style file. Do not start making a style file straight away. This will only lead to frustration.