Providing you have no problem with adding some holes to a shelf unit then you'll be ok.
This can easily be done with any type of unit. But the one in the photo is just a basic unfinished wood one.
All I did was to buy some small silver metal screw eyelets (you can buy gold, brass etc) and some screw hooks with plastic coverings and some white string ( any colour string will do. Something that's not too thin is best as it will not sag and will last longer.
It was just a case of marking with a pencil where you wanted to put the screw eyelets and by hand or pliers, screwing in. Then thread through and tie one end of the string, and when taut tie the other end. Maybe you can find a way to do it a little neater than me? Now hang up those earrings.
For the hooks...... just mark up with a pencil ( I also used a ruler to make sure they were all the same height) and screw in with a pair of pliers. As this was done into a fairly soft wood it was done with ease.
Feel free to use idea.