For herbs, will fresh rosemary & sage work?
My suggestion is to make sure that the vegetables are in a single layer and not too crowded. I like just salt and pepper. Lightly coat with olive oil - not too much. Probably less than you think. Roast at a high temperature (425 - 450); do not move for at least the first 10 minutes, then toss them around on the pan. You might want to use a separate pan for the beets if they are red. Rosemary and sage are fine but make sure they do not burn; consider adding near the end.
I agree with Tarragon, but I always add in a tablespoon of tomato paste - that helps them caramelize and get some sweetness. Make sure you cut the root veg into same size pieces. I usually put the beets in an open pouch of tin foil, then stir in when ready to serve.
Bigpan, love your solution for the beets!