I will agree with the tedious but well worth it opinion. I recorded and tracked my collection here for a few years before I started seriously trading.
I can't speak to what is easiest, only how I do it. I created my wantlist first. This was fairly simple because my want list consists mainly of cards to complete sets. The "Add all missing to wantlist" option is a huge time saver. The option is also available for players and other ways of sorting cards. After having a want list established, I added a trade list. Again made easier by adding multiple cards from the same set. At one point I started adding individual cards for star players, but that was extremely time consuming. I may get back to that but for now I am resorting into sets for adding to the Trade list.
I have also been known to add specific cards to my list to target certain traders that have cards that I want.
I do wish that there was a way to prioritze my want list. I have thousands of cards on my want list, but some are more wanted. I have been offered cards from one set that I need when the same trader has cards from a set that I am focusing on but the trader had no way of knowing that. Of course adding that info would make the input process even more tedious. Double edged sword.