Watch videos of Eric Clapton performing. Pick a song you would like to learn, and watch how Clapton plays it. Observe Clapton's technique and where on the neck of the guitar he plays.
Learn the minor pentatonic scale, also known as the "blues" scale. Clapton, among other electric blues players, will employ this scale in solos. Memorize how to play the scale in a variety of keys. If you can read music or tablature, which is a style of notation for guitar, identify places in a Clapton song that employs the blues scale.
Learn how to play with vibrato. Vibrato refers to manipulating a pitch by quickly moving your left hand up and down or from side to side. Clapton tends to move his entire hand when playing vibrato instead of just a small wrist movement. Watch videos of Clapton using vibrato. Practice in front of a mirror and match your hand movements to those you see in the video.
Learn techniques of playing the guitar and identify when Clapton uses them. For instance, Clapton often employs triplets and accents in his playing. Watch a video or listen to recording and locate where Clapton uses these techniques. Practice holding the pick a bit tighter to make playing accents easier. Practice triplets, which are groups of three notes within one beat.
Choose one riff from an Eric Clapton song. If possible, watch a video of someone playing the riff. Practice the riff in front of a mirror to match what you see and hear.
Learn the gear that Clapton uses. Much of the tone and sound of a performer comes from the instruments and amplifiers they use. If possible, use the same equipment or a variant that sounds similar. Eric Clapton has signature guitars from manufacturers Fender Stratocaster and Martin guitars. Clapton also uses Marshall cabinets, Marshall heads and Fender Twin amplifiers.