I'm sure lots of you know this already but I didn't so I thought it was worth sharing in case anyone else still has to discover this, too.
Like many people, my iPhone is heavy with apps - I have several pages of them. Because my two year old is the boss of my iPhone, the apps also get routinely moved around. I've been meaning to do 'pages' of relevant apps, you know the sort of thing - page 2 is full of 'news apps', page 3 has 'travel apps', page 4 is 'games', etc, but I never have.
What I didn't realise, until last night, was that you can make folders. What you do is hold your finger on an app (any app) until all the apps start moving around in the way that they do, then slide one relevant app into another similar one (eg, the Indy app into the Guardian app). This automatically generates a folder and you then have a chance to name it (iPhone will automatically generate a name, but you can change it). You can fit around 12 apps into each folder (sorry, not counted and my phone is not with me at the moment), but you can have more than one folder with the same name if you want to.
Here's a bit more about it from Apple.