my iPhone is almost full, but I can't see what is on it, and what to remove. In iTunes a yellow bar ("other") - anyone knows what that might be???

Other is a number of things, SMS, mail, etc. How much other do you have? Normal is around 2GB for the newer phones and iOS. If it gets much more over that, it is probably indicitive of corrupt data. Then you would need to restore the device and sync content back.

On your iPhone, look at Settings > General > Usage to get a good idea of what's taking up your space.

"Other" refers to miscellaneous and corrupt files. If it's huge, you can reduce it by restoring your iPhone.

Restore as new, not from a backup. Then sync your content back.

I have done a restore (but I did use backup after) and I have 4.85 GB of "other". On my iphone, it says that 11.6 GB is being used: 5.9 GB music, 80.2 MB photos, 26.5 MB pinterest, 23.5 mb facebook, 19 mb for twitter, no data for videos.

I won't lie - I am NOT great at technology, but I have tried several suggestions from forums. Should I really restore it as new? Is there a way to avoid losing all of my pictures?

You should be importing your pics to your computer as you would a digital camera http://support.apple.com/kb/HT4083

Then you can sync it back to your phone using itunes http://support.apple.com/kb/HT4236 after you restore your phone as new.

I had this same problem. I had 4gb of the "Other yellow bar". I got the yellow bar down to 900mb by deleting all my text messages. The Iphone stores every video and pic you send and recieve through a text/imessage. So I would try deleting your text messages. Hope this helps