Given the large number of base pairs on a single chromosome, the number of hours required to annotate an entire genome can be daunting. Luckily, there is a potential solution; creating a larger community of individuals, like you, who are able to contribute to the annotation process. To become a member of this community, all that you need to do is contribute an annotation.
It is recommended that you start by selecting a problematic annotation from the list of Arabidopsis thaliana annotations created by the GAEVAL Project. You can find that another link to the list at the home page for this tutorial.
Once you find an existing annotation to update and submit, you will need to register with your own unique user ID and password. Once you have built some confidence feel free to take look at other genomes that need annotation. You can find a list of these projects on the PlantGDB Genome Browser Page.
Good luck and happy annotating!