My suggestion (i did it years ago and it worked) :
1- go out foe an hour or two (your choice) and of course your camera, possibly just one lens.
2- set an alarm on your mobile phone (or other device) let say each 5 minutes
3- where you are when the alarm rings take a couple of pictures, without thinking too much
4- back home make a selection, one picture each five or six, according to your taste.
5- try to find something in common among these picture (it could be subject, colors, graphic aspect, light or shadows etc) and maybe this could be your theme for the next days. To be further developed with different techniques (es. use vertical where you used horizontal, go very n ear and isolate a detail where you were away from the subject)
Hope it works for you as well, ciao
robert