Everyone has this. Everyone goes through this at the early stages when they're still learning. Especially me. I am going to cover this one with a simple trick, whether your goal is to just empty out your head or discover your innate magickal divine properties - you will need this in the long run.
You are finding your place of meditation, relaxing, breathing. Trying your best to unwind to reach whatever it is you plan with this practice. But you can't. Mundane thoughts intervene.
We will use my earlier exercise example on with how to shut your brain up
related article - https://steemit.com/meditation/@freesnakes/meditation-practice-clavicula-nox-and-soham-akaal ;
You will imagine a sigil of your own choice and you will use a mantra, SOHAM AKAAL will be perfect for this. As you know all meditation is essentially a breathing exercise.
INHALE: visualize your sigil in your mind's eye
EXHALE: say SOHAM silently in your mind
INHALE: visualize your sigil again
EXHALE: say AKAAL in your mind
INHALE: visualize sigil
EXHALE: say SOHAM
INHALE: sigil
EXHALE: AKAAL
You continue and repeat this for 30 minutes, you continue until you reach a state of mind where nothing is in your way. You can go for longer than 30 minutes if you need, but 30 should be enough time for a day's meditation. You should do a meditation exercise at least once every day for whichever goal you have in mind. Eventually you will get better, as long as you keep on doing it daily.