Spirit guides come in many forms. Can be just whispers telling you which decision to make. Can be in form of animal guide, etc. Mine is bear, and came in dreams (yes, more than one dream). I never tried meditation to have him come. Some people have more than one, each for a different kind of help.
Try this, as I have done it, and was successful. As you drift off to sleep, have it be the last th8ing on your mind to meet your guide. I mean the very last thing, as this will cause a dream to happen. That's how I met mine. But then again he came because he was showing me I was doing the right thing. Spirit guides come to you. You do not demand for them to come. And you have to listen or be aware of subtle things, like a whisp of wind telling you they are with you. Or a voice in your head rather than hearing it with your ears.
Try the dream method, and don't be discouraged if it doesn't happen on the first try. 3 nights, then give it a rest. Then try again. I believe mine came to prove to me he existed, and that he was there for me. Yours will come when they are neede, and in a dream, if you're lucky. Blessed Be...