make sure you’ve set up your author to be included when the patch is merged into the official branch:

git config --global user.name "Jan Kassens"
git config --global user.email "you@example.com"

clone the project:

git clone git://github.com/mootools/mootools-core.git

git fetch

Make changes.

add single files to the commit:

git add <file> <file> ...

git commit

or commit all changed files:

git commit -a

create a patch from the latest commit:

git format-patch HEAD^

or search the log for the patch before your commits, for example: 0300ffea5f8e9910fa761aab129cc0da8f72a6d4

git log

git format-patch 0300ffea5f8e9

now attach the patches to a ticket