Is sweep picking harder to play than alternate picking?
Actually sweep picking is an intermediate to advanced guitar technique so it is considered hard to get used to. As an example, the pattern for sweep picking in this guitar lesson shows an idea in which you can also use tapping. In the diagram you can see which notes are used.
These notes are not too difficult for the fretting hand, but the picking pattern does require the sweep picking technique and that is what most students have troubles with when they first start to learn how to play these kinds of licks. The primary idea behind this technique is to use multiple upstrokes and multiple down strokes. This is done instead of the more common alternate picking approach.
With alternate picking each note is played up and the next is played down. This helps you have more control over your picking, especially when playing fast guitar licks. Sweeping the guitar strings allows you to cover a whole lot of notes with minimal picking motion. This lets you conserve movement so that you actually get more guitar notes out in a shorter amount of time when you are playing a lick or lead.
Here are the Guitar Tabs for this Lick
So to properly sweep pick this guitar lick you should start in the 7th position (your first finger at the 7th fret), and also begin with an upstroke on the first note in the guitar tabs shown here (your ring finger on the fourth string).
Then the next three notes should be down strokes. Next, do a hammer-on to the 10th fret with your pinky finger and then use your right hand tapping finger to do a hammer-on to the 15th fret, then a pull-off back to the 10th fret.
Then do one more pull-off back to the 7th fret where your first finger should be holding position. The last two notes are upstrokes. This completes the entire lick including the sweep picking pattern as well as the right hand tapping part of the lick. Just repeat all of these notes exactly the same way, for practicing purposes or as many times as you need to for the lead guitar part to fit into the song or picking pattern you are working with.
The urge to use down/up picking patterns is strong in the beginning, so taking it slowly is a good idea. Remember that the key to this technique is picking multiple notes with a sweeping motion, either up or down depending on where you are within the lick.
As a further example, this sweep picking video lesson shows an idea in which you can also use tapping and what this all looks and sounds like.