Hi Bora,
The verb s'approcher means to move towards something or somebody ( to go near).
e.g.
La fillette s'approche du chien sans peur = The young girl moves towards the dog without fear
Les randonneurs s'approchent du feu pour se réchauffer = The ramblers go near the fire to warm up
The verb 'se rapprocher' means to get closer or nearer to something or somebody.
e.g.
L'orage se rapproche = The thunder is getting nearer
Nous nous sommes rapprochés dernièrement = We have got closer of late
Hope this helps!