Hey guys, I'm sure you probably get this a lot, but I'm a beginner when it comes to soloing and I'd like to become good enough to play most songs and write my own material. I'm not a beginner to guitar, I've been playing for 3-4 years and I pick up full song rhythm structures in about 20 minutes. Basically, I'd like some help getting started in learning to solo. Where are some good places to start?
I'm in a similar situation to you. I'm not quite soloing yet, but I'm on my way. You have to make sure you can play in time. Heavy use of metronome is important. Train your ear to be able to execute bends exactly right. You want to raise the pitch to an exact interval (or a little higher for blues music). Work on being able to do hammerons and pulloffs as well as several other techniques. Learn scales and different patterns you can play scales in. Then try to fit in licks to those patterns. That's what I've been told. I just haven't put in the work yet. Always remember to be able to play with an intention and a certain feeling in mind and try to match the notes to those feelings, so that if it's supposed to sound sad that it doesn't end up sounding happy.
It depends on if you mean playing other people's solos or writing your own solos.

If it's the former, the secret to playing other people's solos is to have good technique and a good sense of rhythm, same as with rhythm parts. There's no difference, to tell the truth, between learning a riff and a solo, besides the level of technicality demanded of a soloist. The approach is the same. Look at what techniques are used and how they're applied and employ them in the same manner. If you aren't at that level, practice slowly until your technique improves sufficiently that you can play the part.

If it's the latter, the same ideas apply as far as technique goes. However, the extra bit thrown into the mix is that you have to develop some idea of how to translate what you hear in your head to what your hands play. Some folks have a sort of innate sense of melody and can just translate that melody or idea into the mechanics of technique. Most people have to work on that, be it through formally learning theory or forming some kind of informal, reflexive understanding of sound and melody. I would recommend the former case, since far more material exists for learning formal theory than any other method.