So far I’ve only done one chair, but I stained it 3 times and the color still wasn’t dark enough. So I let it sit over night and I didn’t wipe all of the left over stain off because I like it dark. My question is; what can I do

I have a picket fence made from pressure treated lumber. The pickets are fastened to the rails with galvanized finish nails set flush to slightly below the surface and unfilled. Furthermore, the fence is about 8 years old and finished with SW solid white stain. The problem at this point