The key to becoming more efficient when you are at your computer is to eliminate low value activities and replacing them with high value activities. To do this I recommend you take the following three steps:
Step 1) Identify
One thing I did a few months back is install ManicTime. This software allows you to monitor what programs you are using and for how long. It even tracks what sites you visit and how long you are on certain URLs.
Step 2) Collect Data
After a few weeks, I started to notice a few patterns, of how much time I spent on sites or in programs that added no value. Leisure surfing is OK, but I would much rather be building a robot or playing with my daughter, than surfing FaceBook.
Step 3) Eliminate
Stop going to sites or using software that does not add value.