Speed and what to do before adding a unique solution.

Does one solution strategy (or method) have a speed advantage? I try strategies which minimize the number of hints (pencil marks), like finding a completed 3x1 and working in that line or lucky number (see below). Adding more pencil marks is how a computer would solve a puzzle and I am not a computer.

What about peeking at the solution? Peeking slows me down. Usually, all I need is to re-confirm that I have a unique solution. In other words, before adding the solution, I re-confirm that the number is not already used in the 3x3 or 9x1. For me, time spent double checking whether the solution is unique usually prevents an error--fixing broken puzzles slows me down and errors usually end in discarding the puzzle.

In what order should I fill in the solutions? Do other cells carry less risk in making an error? If possible, when choosing between multiple solution strategies, I try to choose the least complex logic. Occam's razor (14th-century English logician and Franciscan friar, William of Ockham)--"... one should not increase, beyond what is necessary, the number of entities required to explain anything."