See my other post for more information on whether away rotations are right for you.
1. Work your absolute hardest, show up early, leave late, and make friends with every single person you encounter.
2. Schedule a meeting with the program director to introduce yourself and sell your top strengths and why you want to go to the program. Compliment the program director and his/her program as much as possible – they like that.
3. Ask for a letter of recommendation from an attending physician you worked with there and submit it to your application to their program.
4. Meet residents and other away rotation students to gauge what they think of the program and just to get advice on residency applications in general.