Once you have gotten to grips with alternate picking and are actively using it without thinking, the next best step is to look at economy picking. This is so closely related to alternate picking, you would think they are the same technique, but it does tale a lot of practice and thinking ahead.
If you're lazy (like I am!) then this will be a great lesson for you. When we alternate pick, we pick up and down on the strings, usually starting on the down stroke. The goal of this technique is to travel as little as we can with out picking hand, meaning we will be able to play quicker, more accurately, and with greater ease! We can do this by starting on an upstroke or picking 2 strings with one movement. Let's look at this with gifs and tabs.
[insert tab and gif here]
If we look at the tab above, we can see that when we alternate pick the melody, we are moving quite a bit but we can make this run a lot more seamless and effortless. If we look at the D, G, B, and E strings, there is a run that can be done in one movement instead of picking each stringg individually. Seeing these runs and knowing that we can do them easier is amazing because we can play quicker and with more consistency, meaning we will sound a lot better! If we were to play this with the picking economised, ti would look like this:
[insert the gif and tab with up and downstroke symbols economised]
See how it looks a lot smoother in the picking hand and how easy it looks? It's because I'm not moving my hand as much as I know that one of the sections can be done with one motion so all I have to do is focus on the fretting hand whilst my picking hand does one motion. Have a look at the melodies below and try to make them as economical (easy!) as possible with your picking hand!
[insert melodies for economy picking]