Glassing is always worthwhile. Assuming the country allows it.
Moving and calling is also a good tactic, even first week. Bugles, IMO, will be better than cow calls for locating bulls since they will be sizing each other up and setting the pecking order. Cow calls will work as well if they are close, but the response will probably be muted compared to third week. Expect a bull that responds to a bugle to come in silently or only bugle back very little. A good tactic is to locate a bull with a bugle, move forward fifty to a hundred yards, then park and wait to intercept him if he comes in. No more calling. Give it some time and see. Wallows are good this time of year in drier areas, and worth a sit mid-day if it's getting hit regularly.
Calling will be hit or miss, and I don't call much early season. Second week it will start to get better. Expect many bugles to be hunters, sorry to say and pay attention to where they come from. Above you, probably elk. Below you, probably a guy on the road. Not always, though.
Elk could be at any level of the mountain in MT. Food is key for the cows, and for you too. Find the food, find the cows, and the bulls will be with them, or higher in the same drainage staging for the rut.
If you haven't, get the Elknut app, or sign up for Chris Roe's course. Learn the calls.
Jeremy