Here is a repost of an excellent post by literary agent Rachelle Gardner, the ultimate resource for writers who are serious about publication.
11 Completely Non-Writing-Related Ideas (On becoming a better writer!)
1. Be creative any way you can. Cook new recipes. Paint a picture. Design a garden. Compose a song. Build something with Legos. Organize the garage.
2. Pay attention. Observe the mannerisms of people around you. Listen to how they speak. Marvel at the way they’re dressed. Notice their shoes and their posture and the look in their eye.
3. Be an armchair shrink. Analyze people’s behavior. Ask yourself how their actions reveal their character. Wonder about their motivations. Scrutinize the dynamics of relationships. Drive your spouse and kids crazy.
4. Live life with passion. Do the things on your bucket list. Stretch beyond your comfort zone. Climb a mountain. Jump out of a plane. Serve soup at a shelter. Dine in a restaurant alone.
5. Take trips. Fly, drive or ride your bike. Dig a well in Africa or lie on a beach in San Diego or discover just how big Texas really is when you drive across it… just go.
6. Watch TV intentionally. Only the best scripted shows and only a few hours a week. Pay attention to good writing and try to figure out why it works.
7. Be a patron of the arts. Theater, dance, museums, concerts, architecture, baseball games. Enjoy beauty, excellence and precision wherever you find it.
8. Spend time everyday in mundane tasks. Do them without any music, radio or TV in the background. Wash the dishes, mow the lawn. Even your commute can be done in silence. See what you find there.
9. Pursue your interests. Have a hobby or two. Besides writing.
10. Exercise. Preferably something like jogging, walking, hiking or bicycling where you have long stretches of a repetitive activity.
(Note- there is one more she posted but I found these ten most applicable!) See her original post here.