It's not always possible to charge your smartphone while traveling outside city limits and into the great outdoors. That being said, there are easy ways of conserving your phone's power while exploring the wild...
Here's what I did on a recent hiking trip:
1. Put Your Phone Selectively Into "Airplane Mode": Instead of going through what apps to switch off, and which settings to modify, a good way to manage your power usage on your smartphone is to simply put it into Airplane Mode. You should see a considerable increase in battery time, and you will be able to continue using most of your services, except the ones that rely on a 3G connection.
2. Wait to Upload Media: While the temptation is great to simply upload any new pics that you've taken immediately, if you're on a hike or trip, it might not be possible. I've grown accustomed to simply taking photos with my native photo app, and uploading them to Instagram and other services once I have access to a power source, like in my car or hotel room (aka #Latergram).
3. Get a Cheap Battery Power Pack: There are some dedicated battery packs for iPhones and other smartphones, but honestly, these type of devices do not last that long, which is one of the reasons I purchased a couple of generic external batteries instead. They usually get my battery from 20% up to 70% in a about 30 minutes or so, and can be easily recharged. The ones I use cost between $20 and $40, and are no name battery packs made in China.
4. More Expensive Battery Packs: If cheap isn't good enough, then you can check out our selection of higher performing battery packs, including the ones from Mophie, which will last you longer, but also cost more.
5. Modify Location Services to Optimize Battery Usage: On iPhones, navigate to Settings > Location Services > System Services in order to check if the purple location icon is displayed in your status bar. If it is, then toggle off "Setting Time Zone". Your battery should last longer, from 30 to 50% more.
MORE TECH AND TRAVEL ON APARTMENT THERAPY:
(Images: Range and Flickr member Kanesue, licensed for use under Creative Commons)
10 No-Fail Decor Tricks & Tips for Small Spaces
Beth's Romantic & Retro Residence
Good Food to Share 
The Big Book of Small, Cool Spaces 
Apartment Therapy Presents 
The Eight-Step Home Cure 
Shaw's Original Fir...
How to Bake a Potato: Three Easy Methods
How To Cook Tender, Chewy Wheat Berries on the Stovetop
I turn down the brightness on my screen - it seems to help.
Yup. For everyday use I just turn the brightness down to minimum. My battery lasts all day and sometimes all night or more, providing that I don't spend a lot of time fiddling on my phone besides the usual functions (email, phone calls, texts). Also turn off all non-essential apps and functions like GPS/wifi unless needed.
If I'm out in the boonies, I don't put my phone on airplane mode, I just turn it off. What's the point of having it on if you don't have reception anyway?
This may already be known to most people, but you really shouldn't charge your phone every night, especially if there's a good deal of charge left. Ideally you should let your phone's battery go down to almost nothing before charging it again. Of course, this is not always possible and can be a pain at times, but it definitely helps, both for daily length as well as overall battery life.
I'm going to have to start using #latergram because that's just too funny.
I just returned from Southern Africa and met some amazing people creating solar panels that are small and can charge any phone. They are designed (read marketed) for folks in Africa but its a fantastic concept, and I'm pretty sure you can find them in the states. They are perfect for camping and hiking! http://www.fti.co.bw
If I had to choose between being without my iphone and spending $20-$40 on several pieces of cheap electronics from China, I would rather be without my iphone. Until China has better manufacturing regulations and more transparency regarding the products they are exporting, I would rather do without than get a "deal" on something that could possible harm my health (by handling it) or the health of who knows how many in China (via their many unsafe manufacturing practices, especially on cheaper goods).
In addition to the other suggestions, quickly double click the round button on the bottom and close all of the open programs on the phone. Press and hold one of the icons that come up and you'll see the little jiggly minus sign. Just go down the row and click on the minus signs until there aren't any left. This closes all the apps you've used and saves a lot of battery time. I was surprised at how many people I know didn't know this.
I have an older phone but it does take pictures... Recently I found a replacement battery online at Accessory Geeks (I think) that was less than half of retail. Now I just carry IT when I'm out hiking...
it's a myth that you shouldn't charge your phone over night. that used to be the case years ago, but not anymore. if you don't use your 1999 nokia, that is.
SAANNEC: what do you think your iphone is, if not a piece of electronics manufactured in China. Sure, it's "designed by Apple in California" - but production is in China, where conditions are far from virtuous. I feel the battery packs carry much more realistic prices than the woefully marked up "design piece" that is the iPhone.
Aperocot - The manufacturing on cheaper goods is much less regulated than the higher end electronics which have some sort of controlling hand from other countries (design, materials, etc). It's the cheaper knockoff goods that carry a much more immediate threat to one's own health as well as the workers' in China and the people who live around the manufacturing plants.
But hey, the importance of saving money by buying cheap knockoffs from entities that have made it more than clear on a global scale that they care more about their bottom line than the health of workers, consumers, and the planet is part of what's wrong with the world now, so why try to make small changes on your own, right? It's six of one, half dozen of another, right?
• Turn down brightness
• Turn of unnecessary push notifications from apps you rarely use, I only have badge for Twitter and Facebook
• Turn of email push/auto check, I've set mine to manual since I have 7 emails setup, mayor battery difference
And sometimes I force quite apps, seems to make my iPhone run smoother, even though they aren't in use :)