In mine, I had kept it as simple as possible, but where warranted I included a 1-liner of information. It is called a "list" of accomplishments, after all, not a resume or CV.
I especially included it when the jury may not know the context of the award or accomplishment being listed.
E.g.
X Scholarship, for excellence in the area of Y Studies
or,
News Editor, ABC Journal
Responsible for research, writing and editing of four page news section in biannual journal.
For a TAship - most TAships are very similar, you may not need to list your duties, unless you did something particularly outstanding like a guest lecture or taught an actual component of the syllabus.
My own headings (again, this was for Fine Art - tailor it to your discipline):
1. Publications, juried / Publications non-juried
2. Exhibitions, juried or curated
3. Honours and Awards, Academic / Honours and Awards, Professional
4. Co-curricular activities
Overall advice: keep it as simple, straightforward and clean as possible - the jury has hundreds to go through! Make the accomplishments speak for themselves as much as possible.