"Concentrate on flying THE NUMBERS and you WILL arrive at the target on time."
Unless the wind is the opposite of what's forecast, unless your compass and DI are out, assuming you remember to make a note of the time at each way point. How do you make sure you fly at 60, 90 or 120kts. A 20 kt headwind component takes 20kts off your cruise speed.
If I'm flying down the VFR corridor from The Isle of Wight to Cherbourg, I'll have a good 45 mins in the air to assess what direction the wind is blowing from and how it's impacting my ground speeding and heading. So far everytime I've managed to pitch up in France within 5 mins of my estimate and within half a mile of my intended track!
Five years of flying, I've never been remotely uncertain of position. Not saying that will last! but my system works for me.
Have complete faith that your sums will get you where you want to go at your peril!!