Any good plan to follow to improve 10km times (sub 45min)

Well, the first thing you could do to improve 10k times is to run quite a bit further than 10k in training.....BUT, do it slower. Sounds like you're trying to run more or less as fast as you can each time you go out. With absolutely zero research to back me up, I reckon a good percentage (15? 20?) of amateurs do that and roughly 0% of elites! You'll need to vary your training, do some more if at all possible, say five times a week and do some slower than 'normal'. There's an old thread or two on here about 10k training. Search them up. There was a McMillan's 10k training plan that a few of us used, but it wasn't universally liked.