Iphone 4 won't take some songs?

I hooked up my phone to itunes and picked up a couple of songs but of the songs that have been checked about 90% come through but the rest of it won't sync. Sometimes when I've clicked sinc the bar showing how much GB is left grows to indicate the songs it wants to add but then it syncs and finishes and the bar reverts to the level it was at before. What do I do?

Don't sync. Did you think you needed to?

I never sync any of my Apple devices to put music on it. Instead my iTunes is set for manual management of music and video. I almost never have problems putting music on my iPod and obviously much fewer than those complained of in questions like yours which are posted here in the thousands - including putting songs on my iPod.

Manual management is just clearly superior in every way and it works on iPods, iPhones and iPads both new and old. I've tried it on first generation nanos, iPod 4, iPad 3 and iPhone 5

You enable manual management by bringing up sidebar in iTunes (ctrl S if you don't have it up already) and clicking on the iPod tab. The main window should show you the main summary for your iPod. The box for the manual management option is at the bottom of the page (it's probably already checked).

That's basically it. Now you can just drag the songs from whatever folder they're in in WIndows and drop onto the iPod tab on iTunes sidebar.

Every time you update iTunes, you need to reboot your computer.