Go to Settings>General>Usage and see what apps are taking up the most space and delete any your don't use.
My other recommendation is to use iTunes Match and only download the songs on your iPhone that you use most often, leaving the rest in the cloud. That way you take up minimal storage with music, but can always have your entire collection available when you need it.
Also, you say photos take up a lot of room. Uncheck "include videos" in iTunes under the photo tab to save some space.
Take some or all of your vids and photos OFF your iPhone. You can access the photo file directly using your computer and a USB connection ...
USB connect iPhone to computer > close iTunes if it opens > open main computer where drives are listed > click on iPhone > open folders that show up until you get to DCIM ... this is where your photos and videos are stored (you may have to open another one or two folders within DCIM to find them)
Then, drag and drop your photos from the iPhone to your PC/Mac. Then delete from your iPhone those photos you transferred to your computer. Presto - instant room in your iPhone memory. Photos and ESPECIALLY videos are HUGE memory hogs.
Just connect your iPhone to your Mac and use iPhoto to import your photos and videos. After they are imported, it will give you the option of deleting them from the phone. If you don't have a Mac, I'm sure there are photo managers on PCs that will import as well.
You can then selectively choose which photos, albums, events, etc. that you want to add back to your phone through iTunes. iTunes will talk to iPhoto to present your options for syncing photos. It all works really well.