I was one of those people, but not any more. Here's how I went from an iPhone that was dead by early afternoon to one that can keep going for around 24 hours of normal usage.
First of all let me define normal usage. There are two sorts of iPhone usage: active and passive. Active usage being things like calls and photos, passive usage being apps that run on their own, like email and twitter.
My weekday usage pattern looks like this:
30-45 minutes of bluetooth music streaming in the car, screen on.
15-30 minutes of voice calls
20-30 SMS messages
20-50 Facebook messages
60-90 minutes of web browsing
60-90 minutes of reading ebooks
Heavy usage of Siri for reminders and notes
Capture of document images into OneNote / Evernote
In all my phone is on, in active use for four to six hours every day.
Passive usage amounts to background sync for two exchange email accounts and two personal email accounts; Google+, Twitter, OneNote and Evernote background refresh; and cloud syncing for the various cloud storage accounts I use.
As I said, previously this would mean that my battery was dead by early afternoon, unless I plugged my iPhone in.
So what did I do?
First of all have a look at the applications which you have allowed to use background app refresh. If you're anything like me you've just given every app carte blanche to run in the background irrespective of whether there's any utility in doing so. Go into Settings and disable anything that you don't need to have refreshed in the background. For me that meant disabling sixteen of the thirty-one apps that I had previously allowed.
Next trawl through Notification Centre and disable notifications for apps that you don't need to be notified for. Make sure you turn off the notification fully - especially the sound, otherwise the temptation is to pick up your phone to see what's new, even when the notification is unimportant. Bad for battery life, bad for productivity.
Finally look at the brightness of the screen. Even with auto brightness set you can set an overall target brightness. Drag the slider to the left by a couple of notches, you won't notice the difference onscreen but it will help extend your battery life further.
It will probably take a couple of hours to work through all of these changes, but in the end the results will be worth it. The screenshot above shows just how much my iPhone 5 can get through in a normal day's use.
Hopefully the bigger battery in the iPhone 6 will mean that these sort of things won't be necessary.