Protect from excess HandlingSorting out Baseball cards would be a collectors preference. The priority should be keeping them protected from being damaged. If you are going to handle the cards often you might want to invest in pocket pages kept in a loose leaf folder. You can then view the cards without handling them but keep in mind if you are going to take them in and out of the page you will risk damaging the cards. Single plastic card holders are a good choice but it could run into a lot of money. In that case use the card holders for the key cards that you might handle the most and keep the remaining "commons" in a collectors box.
or you can just sort them by teams or how much money each is worth