What Do I Do With This Thing?
The problem we usually have with scales is that the scale is learned but then there is no explanation of how to use it. Most musicians go through their scales once in a while and then forget about them and get to practicing 'real songs'. The fact is that as soon as you learn a new scale, it should be explained how to use that scale. There are many things to learn about how to use scales and how to make beautiful music, but it's not rocket science. It's an ongoing skill that must be developed. As soon as you learn a new scale, you should be making music using it immediately.
So What Now?
Say you've learned the A minor pentatonic scale. So what now? First off, make sure you've got the fingering under control. Second, pick a song in that key and start messing around with the scale. Start in the middle somewhere and just mess around. Yes, there's a lot more to it than that, but we don't care. We're going to start using it right now. Try repeating notes, jumping from a low note to a high note. Try repeating the same couple of notes in a row. Try different rhythms. Try playing a couple of notes, then repeat the same notes with a slight variation. That's it; you're making music with your newly learned scale. Sure it may not turn out to be greatest piece you've ever done but that's not the point. You're learning a new language and you're starting to use the language.
The Language Analogy
As you know, music is like it's own language. Like a language there are grammar and structure rules to learn. These don't always apply to all situations, they are mostly guidelines. Like a language, you must learn the structure of the language while memorizing common phrases and idiosyncrasies. That's what you're doing when you learn your scales, you're learning about the basic structure under the language. It's still up to you to use that structure to express yourself. This occurs when after getting familiar with the language; you become better at expressing yourself. You start using the correct grammar and complete thoughts, instead of rehashing common phrases.
Merry Melodies
The best way to start using scales is to try and create music and melodies right from the start. Continuing with our language analogy, music acts a lot like our speech. When we talk, we speak in phrases. We make a statement, stop, breathe, make another related statement, stop, and repeat. At the most basic level, music phrasing is the exact same thing. Have you ever heard somebody rambling on, over and over, with no stops in between? Annoying isn't it? Same for music. Try playing a couple of notes from your scale, one phrase at a time. Pick a couple of notes and play. Now, instead of just rambling on, stop, breathe, and then continue on with your next statement. Try and have the next statement relate to the first phrase that you played. What this means exactly is completely up to you. Everybody expresses themselves differently. As long as you have this in mind when you're playing, it'll start to come across in your playing.If you can, record yourself. You may be surprised and hear some hidden gems in there.
Don't Forget The Beat
Always try and have one ear on the rhythm. Play a couple of notes but try and make them fit into the rhythm of the song. Most songs are built from 8th notes. Try building your phrases using these to start. If you don't know what the basic beat of the song you are playing is, tap your foot. These will typically be quarter notes. Try a medium tempo. Try quarters to start if you're not sure about using 8ths. The rhythm is very important. Varying the rhythm on the same couple of notes has a huge effect on the outcome of the phrase.
Start Exploring Now
You will learn as you go that there are a lot of things to learn when creating melodies and phrases. It's an ongoing journey. As you explore, it'll become easier and easier to make statements that are pleasing and musical. Most of all, they will be your phrases, your personality. Along the way, you'll learn other solos, phrases and melodies. These, like phrases in our language, will become part of your musical vocabulary. But, if you've practiced your scales properly, it'll be easy to incorporate them into your own style. Try to create music from the very start; what will come out, will be uniquely you.