A practice I learned from another teacher was to just practice being aware of what comes to your awareness and don't chase it out, just be aware of it.
You'll be amazed how quickly random thoughts die when you just watch them with just the intent of watching.
Go for 5 minutes. Every 4 seconds say in your mind what is happening. Everyone 1 second if you need deeper foundational work. Try to breathe in for 4 counts, then out for 4. Later when you have a handle on that, do 4 counts in, 4 counts hold without closing your throat, 4 counts out, 4 counts holding without blocking your airway.
Place your focus right behind your eyes, you may feel them tingle a little bit and this will also help you focus on keeping focus on your mental screen.
If your mental screen is just stillness in your mind, say "clear"
If a visual thought pops in, say "thinking"
If you feel an ache or tingle somewhere, say "feeling"
If your attention is brought to a sound outside or a memory of a tune, say "hearing"
And just stay with awareness of that thought, as if viewing as another objective viewer, no shame or emotions or judgment, just *being* with it. But do be aware of what emotions do stir up, if it is negative, it's indication of where expression and healing and forgiveness probably needs to take place.
This way you begin to develop the training wheels of being aware, so you can be aware consciously when you are meditating and focusing on having no thought generation of your own, so that when OTHER thoughts come in, you are aware them and can begin to distinguish your own from external thoughts you picked up on.
Also be sure your spine straight and aligned and your chin *slighty* tucked in, this allows proper energy flow and healthier breathing.
Do not be a little bitch with what may pop up. You *want* unpleasant stuff to pop in because then it may express itself and may leave. If not, the bad memory or thought stays to ferment and prevents proper energy flow which then can manifest later as "random aches" where the energy/memory is stored and other emotional and psychological issues begin to fester.
If you can't handle a certain thought and focusing on it with gratitude or a blank expression doesn't make it leave, just state in your mind with authority "I banish the thought", or "I reject that thought" and visualize it rocketing away from you into the darkness. The same thought may return over and over again, and you will need to repeat it over and over until it sticks, perhaps dozens at times at first in rapid succession. In a few weeks of consistently banishing thoughts, your head will be spinning how instantaneously and without fight thoughts vanish. I was disappointed myself the first time because I was so assumed to "mental sparing."
Saying "Gas yourself" to thoughts and visualizing them being thrust away and locked into a gas chamber would be hilarious and stimulating to your subconscious since you probably have your own culture shaped from Holla Forums culture.