Lol nice comment silver and another great sketch FossickingKid! Finding a perspective or vanishing point can be tricky and your off to a great start with this new image mate.
I've noticed recently in op-shops that the hand-pump Crayola air-brush has been showing up heaps and bought one for my daughters for $5. For a cheap airbrush and using textas...it is a fun toy you may want to look at getting one day and have a go mabey stenciling or airbrushing
Best advice I can give you is save up $50 and go to your local art supplier or newsagency and buy a selection of:
Greyleads - all hardnesses hb..sb..sh..etc
Charcoal pencils
Skin tone pencils
Ink - this means fine liners of various sizes, texta and also paintbrush ink / caligraphy ink
A good eraser like the soft putty eraser will prevent smudging
Water & oil color paints + brush
When you draw, keep a habit of keeping a scrap piece of paper under your pencil / drawing hand so you don't smudge your work
There are many ways to learn to draw, feel free to ask any questions. I'm not totally awesome or H.R.Geiger, but I used to be a great drawer. Nearly lost the touch
Best of luck mate, you have the talent!
Oh - whenever you get the chance..draw. do it as much as you can. If you can't think of what to draw, grab any boring object and try to draw it as realistic as you can with shape, perspective and shading, instead of thinking of what to draw, as I know this can be an issue and spend a lot of time just 'finding something to draw'. Even if its a pencil..drink bottle or silver coin someone detected off the forum.. try to draw it all
Hope my post isn't too confusing for you buddy