Posted: 30/09/2014 at 11:23
It's all very individual: you sound like you might be one of the lucky souls in decent nick to start off with, who can just pile in and yet stay off the injury bench.
"Tired" is OK. "Problems sleeping", "Grumpy", "a niggle that has stayed in the same spot for a week", "feeling like concrete EVERY morning", that's the sort of thing you need to keep an eye out for.
Sensible ideas are :
* keep an exercise log which also includes how your mood is and how you ate and slept
* do things like strength (especially core stability) training, cycling, yoga or swimming, on your non running days
* join a local club or start going to parkrun to acquire a lot of new friends to talk running with (and see how they screw up or succeed!)
* have a protein+ carb snack ready for immediately after the run (peanut butter sandwich? Milkshake?)
* do proper warmups and cooldowns after intense (speed) sessions (if you join a club and do speed stuff with them, they should do this)
* keep an eye on your diet - google Diet Quality Score
and above all, ** enjoying it ** is actually a surprisingly good guide: "if you're happy and you know it" you're probably not overdoing it