ATCnoob
keep plugging away at it, strip scanning is a common problem for trainees, especially in the early stages.
Always ask yourself questions about the aircraft as you look at the strip - that way it will hopefuly force you to take the information in and act on it, instead of just staring blankly at the strip!!
It is a pain, especially to begin with, but try to persevere and hopefully it will come together. OJTIs can't read your mind etc, so they can only pick up poor strip scanning technique by witnessing a student missing 'the obvious' (only obvious to experienced people).
As you get more experience on the sectors, even as a trainee, you will be able to rely less on strips and more on other sources of information and will do things based on that info.
This way, the OJTI won't be as assured in being able to pick you up for lack of strip scan - they can only do that when you fall behind or regularly miss things. (Mind you, if you stare at th eradar and do everything off that, it is a bit obvious too!).
It's a bit of smoke and mirrors - but at the end of the day, to begin with you need to get the strip scan fairly nailed. Jus remember you are not unique in feeling tha it is not coming together, and certainly not unique in being picked up for it.
If you are currently on TVC , you will know that your colleagues on course are being picked up for the same things. It is normal, but that doesn't mean that you can get away with not working at it!!