Ok, so I’ve been riding for 3 to 4 months and I can ride with one foot, ride SIF, idle, idle with one foot, hop, crank stall, mount in various ways and 200 degree hoptwist but I can’t ride backwards or 180 unispin! Any advice on how to do these things? Greatly appreciated. 
dude, honestly do a search! 
a great resources, use it to your advantage. If it is no good for you, here is my advice.
Both tricks rely mostly on practise rather than technique, unispins require alot of balls at first but once landed, becomes second nature. Jump as high as you can, have both hands on the seat, spin it, then bring your feet in as far as possible. The thought of landing on the cranks rather than the pedals is comforting to some and is a good way of landing them for the first time.
As for riding backwards, be sure than you are as controlled as possible forwards before you try backwards. Lean back and pedal as hard as you can.
As I said before, practise makes perfect.
Jas
Thanx Jas i’ll go practise now
really, the main thing is…i know you’ve heard it before, is just practice your ass off. its really the best way, tips are nice but they key is practice as much as you possibly can.