If you’re primarily concerned with speed, use a wall charger or external battery pack instead of your laptop’s USB port. It might be less convenient, but it’ll allow to your transfer more amps of power to your iPhone at once. That means it’ll be faster.
That said, while you shouldn't trust most third-party Apple accessory makers, there are chargers from reputable brands like Anker, Monoprice, and AmazonBasics that are both faster and trustworthy. They won't be dirt cheap, but the safety is worth the extra buck or two. Just make sure it has Apple's MFi (Made for iPhone/iPad/iPod) certification on its packaging.
Again, it’s all about how much current these things supply. Apple’s default charger puts out about 1 amp, even though the iPhone is capable of drawing up to 2.1 amps. Something like this $11 option will put out more juice. Alternatively, if you own an iPad, the stronger charger that comes with that can work just as well.
Maybe remove that case.
In other words, keep it cool. The lithium-ion battery in your phone is a physical, delicate thing, and as a result, it doesn’t play nice with extreme heat — the kind that some tight-fitting cases can trap over your phone while it’s charging.
Apple itself says that keeping the battery in a room-temperature climate will get you the steadiest results in the long run.
Take some of the weight off your phone’s shoulders.
While maybe not a charging tip, being mindful of everything your phone is doing will help better preserve your battery in the long run.
You can shut the screen off, for one. (Or at least turn down the brightness.) You can dig into the notifications menu and turn off push alerts for lower priority apps. You can download those videos and songs you want for your commute instead of streaming them. You can disable location services or mobile data when you’re not using them. And so on.
You don’t have to go crazy with this stuff — lots of programs are designed to be efficient with WiFi, Bluetooth, or GPS, and you don’t want to cripple your phone’s utility. You just shouldn’t go all out all the time.
Turn on Airplane Mode, if you’re really in a bind.
If all of that isn’t enough, you can get a little bit more from your charge by enabling Airplane Mode. Ostensibly designed for, you guessed it, airplanes, this shuts off the radios for things like cellular data, WiFi, and Bluetooth. Charging with that stuff disabled will save you a few minutes than it’d take otherwise, depending on how long you’re plugged in.
The trade-off is that you’re disconnecting yourself from the outside world. There’ll be no calls, no texts, no notifications. That kind of defeats the purpose of a smartphone in the first place. Still, if you absolutely need to get as much life as you can, it’s something.
Apple implemented a less stringent version of this idea called Low Power Mode into iOS 9. It works similarly, just to a lesser extent. It can help in a pinch, but it makes your smart device dumber.
It’s also slower. With those cases, I found it to take an hour longer to get to the same point using traditional methods. If you’re not in a hurry, it’s a nice thing to have, but then again you’re probably not reading this article in the first place.
Make sure there's no debris in your Lightning port.
As simple as it sounds, sometimes you may not get the most out of your charge because lint, dust, or other debris is physically blocking your port. You might be fine, but if you suspect some blockage, try taking a toothpick or paperclip and carefully clean the space.
BONUS: Hope really hard that Apple has a faster charging solution with the next iPhone.
Okay, so this isn't really a tip. Nevertheless, if Apple won't boost the size of future iPhone batteries — and all signs suggest that it’s not — it’d be nice if to see it implement some sort of turbocharging similar to what many Android phones have with things like Qualcomm’s Quick Charge standard. That way, you wouldn’t have to resort to being crafty like this.