Tie your tie the way you like it.
Get a marker of some kind and make a mark on the back of the long side above the knot. (White dot)
Make another mark on the back of the tie where it comes out the bottom of the knot. (White dot)
What you have done is marked the length of the tie it takes to make the knot.
Step 2: Look at picture 2
Take your tie off and measure the distance between the marks.
Step 3: Look at picture 3
Take this measurement and make another mark up from the bottom tip of the tie.
When you tie your tie the next time, place this mark where you like the tip of your tie to be.
Some men like it to be at the top of their belt buckle.
If your ties are all the same, mark them all now. If you have ties of different widths or thicknesses of material, you might have to do this on all the different ones.
Now you can have perfect length every time without having to tie your tie over and over again.