http://maps.achievementhunter.com/guides/overview/grandtheft...Here is a link to a great map for collectibles. You can also use the rockstar social club to track all the collectibles and see exact locations of ones you haven't found yet. I used it for 360 version and will be using it for the xbone version.
Update: Just completed on Xbone. The mapped linked above has video for each item that it very usefull. The rockstar social club updates to reflect what you have found and are still missing. Both make these collection achievements very easy.