What is the most successful approach to link two points using PTP (point to point ) through long distance antenna , (wireless connection) ?

The use of a narrow beam high gain LOS antenna for long distance communications. This would also require a relatively high amount of Tx power and the use of unused frequency space to reduce interference.

If you would like to connect 2 networks via Point-to-Point...there are several vendor solutions you can use. One of the easiest vendor products I have used was Trango Wireless.  ( https://www.trangosys.com/ ). Very easy to setup, configure and manage.