You don't have to make marks onto your pic.
Without tensioning the lock, set your pick on the first pin. You can see this pin, so this is easy. No close your eyes and get an impression of the felling if you slightly move forward or backward your pick. Now try to place your pick onto the second pin (with closed eyes) and look afterwards if you were correct. Try some time, without tension and looking into the lock, to just feel the pins and depress them. Maybe this helps.
As a beginner, I had also problems with placing the pick on the pin. But later I learned how to fell the important pins. If a pin is not set yet or not binding at all, you will not feel this pin strongly. However, if you accidentally touch this pin, this won't matter (except for high quality locks where all nearly pins are somehow binding at the same time!) at all.
Please also refer to this excellent beginners guide:
viewtopic.php?f=3&t=10677I also build up very early my easily repinnable lock. I replaced the retaining pins of each bore with headless screws, so I could easily remove and exchange pins without dismantling the lock or even have to pick it. With such a training lock, you should follow the above mentioned and linked tutorial.
(noob tips )
