I'm always tired, but I have noticed I feel MUCH better when my hemoglobin is above 10. 
I am not iron deficient, and I have no idea what can increase my hemoglobin. Most reports nowadays I manage at hb 9. And I am mostly tired.  But I have earlier reports where my hemoglobin had reached 10.5.
So how do I reach 10.5 again?   :-)  My B12 is also higher than normal, so I go easy on the supplements now. Vit D is also higher than normal.  I take folic acid daily.  Started Vit C for I have recurrent cold/sore throats.
Also does erythropoietin help if one has a normal-to-high RBC count? What about side effects? How long does the hemoglobin stay increased? 
Exercise helps me increase stamina, though its too early to tell.