Just received core AD&D books and some supplements. Advice before I begin?

A friend of mine saw me browsing through his AD&D books and let me take everything that had a double, which was a lot of books. I now have the PH, DMG, L&L, Magic Encyclopedias I & II, and the Complete Fighter's Handbook. Just wondering if anyone has any advice or tips for me as I've only GMed for D&D 3.5, 4e, and All Flesh Must Be Eaten.