I would recommend using gel pens (vs. ballpoint). These let you write on paper with a lot less effort compared to ballpoint, allowing you to write faster and without getting tired as quickly. If you don't already do so, you should write smaller (~15 words per line) and with very finetip pens, so you can cover more words in the same amount of time.

In high school, these were my favorite pens: http://www.jetpens.com/product_info.php/products_id/82