Relaxation methods only work temporarily

During meditation I have discovered two methods of relaxing

One was to let the feelings of tension amd unrestlessness to come to me and the other one was ro release the tension while and the letting the tension come to me worked good for a while

And the realising the tension while breathing out method worked well for one night but stopped working after that night

I'd like to meditate but can't if I can't even get my body to relax bur I don't know what I'm doing wrong here