My railings consist of select cedar 4x4 posts @48" on center, capped with a select cedar 2x6, with a 2x4 rail under the cap to which 2x2 cedar ballusters are screwed to at the top, and the deck skirt at the bottom.
It works like this...
Predrill your posts for 3/8" zinc dipped bolts. (NOT SCREWS, BOLTS!) You want to do this by using a spade bit to drill a 1" hole the depth of the bolt head and a 1"x3/8" washer, usually @1/2". (I put blue tape on the spade bit to help with depth consistency...) After you do the 1", then drill STRAIGHT through the post with a 3/8" spade bit.
You will use 2 bolts on a deck built with 2x8 joists or smaller, or 3 on joists bigger than 2x8, staying away from the extreme 1-1/2 of the top and bottom of the joist. If you want to get artsy about it, you can take a 45* cut off the bottom face edge of the post, so the cut is about 2" wide. (an inch and a half from the bottom, cutting to the bottom)
Attach the post to the outside of the rim joist on your deck with a couple large c clamps or bar clamps, make sure it is level, and that the top of the post is 34.5" above the level of your deck boards. Then drill through the predrilled holes in the post through the joist, then bolt the post on with the 3/8" bolt, a 1" washer, the post, the joist, a 1" washer, a 3/8" lockwasher, and a 3/8" nut. Torque those suckers down really well.
Next, screw a cedar 2x4 to the inside of the posts at the top, so that it is in the same plane as the rim joists. Ideally, using a 12" 2x4 that can span more than 2 posts works best. Your 2x6 cap will span the gaps in the 2x4 rail, and will sit flush with the inside surface of the 2x4, covering the 2x4 and the post top, and hanging over the far edge of the post by about 1/2".
Your ballusters then screw to the 2x4 rail butted up to the bottom of the 2x6 cap, and screwed to the outside of the rimjoist. I use 1 screw at the top, and 2 at the bottom.
What makes the rail super strong is a deck design where you can take advantage of right angles in the rail cap. This allows the rail to support itself in X vs. Y movement.
I apologize if this is wordy or doesn't make sense, but I assure you the rail comes out strong as heck.
I don't like notching the posts because you create a situation where the endgrain of the post sits in water on the deck surface, which is BAD. Notched posts always seem to rot around here.
Good luck, post back to have me fill in anything I left out...