Should i play lots of exercises ( tehnique exercises ) or is it enough when i play songs , scales etc ?
This is what I normally do daily.

Little warm ups - exercises - Some songs - Then some more exercises.

Works for me. And when I play songs I kind of do little exercises in between them and vice versa if you know what I mean.
depending on how much you play. if your like me you should spend at least 33.3 percent of your time doin excersies, especially when you first start. eventually you'll find really difficult songs that you use for excersises. like for me its doing the song "eugenes trick bag" its very difficult (for me) so its a very good warm up. (but you dont start out nearly as fast as your capable of playing.)