What is your past hunting experience? Where did you come from? Have you don't much blacktail hunting in the past?
There is a lot of ground for you to hunt in Snohomish County, pretty much have to be East of Hwy9 to use a rifle, and even then you need to know if there are firearm restrictions in the area. You will pretty much have to get out and walk behind closed gates unless you buy a Weyerhauser permit for their lands. My general rule of thumb is if you want to kill a deer, hunt lower in active timber harvest areas. You won't be alone most likely, and big ones are harder to come by. If you want a chance at a big one and don't mind eating your tag, hunt higher in the sub alpine and big timber. You will be alone, won't see many deer most likely, but a shot at a big ones is real.
Recently I've been behind gates in 5 different areas in Skagit and Snohomish county and found deer in all of them. Just have to be willing to put your boots on and go.