Lots of ways to go at it really. You can use commercial pore fillers or fill with just True Oil. It takes some effort to do a level mirror finish with True Oil, but the results can be stunning.
My methods have evolved a bit, but its basically just build it up and block it down. Here is a brief rundown on how I did this latest one.
The the bulk of the filling is by wet sanding with Tru Oil and 400, usually 2 sessions gets me mostly there. Then I do 3 coats a day for 5 or so days until I get a good level body going. I wipe it on using some 2 1/2" x 2 1/2" cotton gun cleaning patch's, ran out of old t-shirts. Forgot to add, I wet sand it with 1000 grit and mineral spirits before the start of that days coats.
Once I've a good film started and most imperfections filled, I spray 3 or so coats, (one a day), with a little detail gun. Again, I wet sand each day before that days coat, but move to 1500, then 2000 on the last two coats.
I've used the Tru Oil rattle cans and it works fine. I mix my own and spray with a small detail gun because its cheaper. You can thin Tru Oil up to 50%, thats 2 parts oil to one part mineral spirits.
Here is the back of a steel, its mahogany and maple
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http://i54.photobucket.com/albums/g94/quar...04/R-004-17.jpg