You have three screws that you can turn and you will need to remove the gun from the stock.

The screw in the back of the trigger at the top (D22) adjusts the triggers creep. There is a set screw (D44) that goes through the same hole but in front of the trigger that will need to be loose before you can adjust the one in the back. Once you have it adjusted make sure you retighten the set screw in the front.

There is another screw where you put your finger (D43). This screw presses on a spring and adjusts the trigger pull weight.

The third screw is the over travel adjustment (D45). This one it pretty self explanatory. Screw it in to reduce over travel and out to get more over travel.

Here is a PDF link so you can view a schematic.
http://www.ruger-firearms.com/firearms/PDF/E5.pdf


If you don't have the utmost confidence in adjusting this trigger system take it to a gunsmith. It's not worth getting hurt over the $30 he would charge you to adjust it properly.