I used to flyfish Canim Lake every summer for a week in august. Family vacation with a fishing worked in. Previous comments are exactly right. Big lake and big water so watch out for wind. I found around any weed beds was good fishing. There is a large creek that comes in about 1/3 of the way down from the west on the north shore. If you look on a map, there is a V shaped bay with the creek at the top of the V. This bay is full of weed and good fishing on the outside edge with leech, spratley and the like if there are no hatches. Also Jim Creek comes in about 2/3 of the way down from the west on the south side. Looks really barren as it is a gravel and sand beach, but a beetle pattern chucked into the creek outflow and let drift into the lake can be good. There are lots of weed beds at the west end but there is a no fishing zone there also. Also some weed beds out in front and east of Rainbow Resort that were not bad. Small lakes in the area, like Howard are far better for fly fishing but but you can make the choice .
Hope this helps a bit, tight lines..........