Hi there!
I'm working on a board around an ATtiny841 ant here's the schematics I came up with:
link to picture
Are there any obvious errors on my schematics or it' ok?
The 1M resistor is unnecessary. I have never found a need for 0.1uF cap on reset.
If planning to program via serial, you need a 0.1uF cap between the DTR line of the serial adapter and the RST pin (and the other cap from RST to ground must not be present).
If wires from power supply to board will be long, a larger cap, say 4.7 or 10uF on the board would be advisable.
Otherwise looks good.