There might not be any such thing as 'all at once' whether its in quilting or in life. It might be unrealistic to expect a quick, flawless, or smooth journey.
For me, its more about my expectations. If I have learned anything, it is that no one is perfect, and no project is perfect. Often, I seem to get the skills I need as I go along, especially when something isn't turning out the way the pattern says it should.
Three of my quilt tops are not quite done. One (The Great Pumpkin) needs at least one border, maybe two. This will take a trip into the big city with the unfinished quilt in hand so that the olive green I think it needs for that last border can be a close-to-perfect match. The second border might be just black to continue the comic book frame look.
One quilt top (Winter Golfers) needs appliques on it. I haven't started on them. I haven't even started thinking about them.
One (a Mystery Quilt) needs piecing of all 30 blocks. When that work is done all all three quilt tops, they each move into the stage of basting.