And most of the time, you really don't have much to do except moving workers around tiles to do improvements and then just hit enter to end the turn. Don't know and understand what I am researching quite often too.
There are several other things you can do on each turn, including checking to see if it's possible to whip anything when you're running slavery, checking all your trade deals to see if any new ones are available or can be renegotiated, reassigning citizen tile assignments and/or specialists, etc., etc.
As for research, have a close look at the tech tree. Each technology gives you a new ability such as seeing the location of strategic resources (and accessing them), the ability to build new military units, buildings, or wonders, changing civics, and so on. Most techs also lead to other techs that grant additional abilities.
As I said above, set some in-game mini-goals for yourself (I call them mini-goals because the big goal is to win the game). Use the tech tree to guide you to the achievement of these mini-goals. Here are a few examples.
- In the early game, many players like to focus on acquiring the "worker techs" that allow your workers to build new tile improvements and access resources. The early game worker techs include the Wheel, Mining, Hunting, Agriculture, Pottery, and Animal Husbandry.
- If you want to try an early rush, go after military techs that reveal strategic resources and/or enable strong units. Early rush techs include Animal Husbandry (for horses), the Wheel (for Chariots), Bronze Working (for Axemen) and possibly Iron Working (for Swordsmen).
- If you want to build a wonder, pursue the tech that enables the wonder as well as a tech that allows you to access a resource that accelerates the build of the wonder. For example, if you want to build the Pyramids, research Masonry, which both enables the wonder and allows you to build a quarry on a stone resource (assuming you have one nearby) that will make building the Pyramids faster. If you want to build the Oracle, research Masonry (so you can quarry marble) and research Mysticism, either Meditation or Polytheism, and Priesthood.
Try to base your goals on your leader and his/her traits, civilization, starting techs, and map. If you're playing as Rome, for example, you should be going after Iron Working ASAP (starting with the Mining tech in hand gives you a head start) to build Praetorians, Rome's awesome UU, then using them to conquer your neighbours; founding religions and building wonders is a waste of time for the Caesars. If you're playing as Gandhi, however, it makes more sense to either research worker techs to take advantage of India's UU, the fast worker, as early as possible, and/or leveraging the Spiritual trait and having Mysticism as a starting tech to found a religion.