Generating Tiles with QGIS?

For QGIS 3.8 or greater, generating tiles is built in - you can find it in the Processing tool box as Generate XYZ tiles (Directory) and Generate XYZ tiles (MBTiles).

I recently came across a new plugin for QGIS 1.9 called QTiles. It's development was announced Dec 2012 on the QGIS Developer forum.

QTiles designed to generate raster tiles from QGIS projects according to the Slippy Map specification [0] and supports two output types: directory and ZIP-archive.

While I haven't personally used it, it looks very simple and easy to use.

It is possible to generate tiles using python console, you can read about it here. Keep in mind, that you might need to modify the script.

However I would encourage you to use mapnik for generating tiles, as above mentioned qgis script did not work well for me.

Styling map is easy with xml for mapnik, you will not have any trouble with it. Some modifications for quantumnik will let you generate tiles directly from qgis.