Life on earth has taken four billion years to evolve as far as technology. The probability of another planet having life that just happened to reach technology at the same time as us is therefore infinitesimal. If intelligent aliens exist, they will almost certainly be far in advance of us, perhaps by millions or even billions of years. There are no easy answers. We have only Homo sapiens to go on, with scant idea as to how many of our prejudices are accidents of evolution and how many might be universal.
Most experts think that maths is the key.
After all, as Galileo remarked, the great book of nature is written in the language of mathematics. The universal mathematical laws that enable us to build and operate radio telescopes should be familiar to alien radio astronomers too. Mathematics is the product of the higher human intellect. Clearly Seti leads us into some very deep waters. We should not be put off by this, however.