There are many different ways of getting back on track.
Here's the one I teach my students. But it is harder to explain in words something which is essentially pictoral, so you really ought to discuss this with your instructor.
First of all, you have to do the preparation on the ground. Draw "10 degree" lines on your chart - on either one side or both sides of your planned track, draw another line which starts in the same place as your planned track but is 10 degrees off. Make sure you do this in a different colour to your planned track, so you don't confuse the two.
Then, when airborne, get to your start point, turn, start the stopwatch, and do any r/t necessary (turn, time, talk). At regular (but not too frequent) intervals, you will then fix your position by checking your stopwatch, figuring out how far along your track you expect to be, looking on your chart for features which should be ahead or to the side of you, then locating those features out of the window. If I understand your question correctly, you are already happy with all of this.
What I think you are asking is what to if you manage to fix your position as being slightly off of your planned track?
Let's have an example: your planned track is 054, your planned heading is 044. After 7 minutes, you fix your position as being overhead a small town which is actually slightly to the left of your planned track.
Using your 10-degree line which you drew before you started, you can easily see how far off track you are. For example, if the town you are overhead is just less than half way between your planned track and your 10-degree line, you are maybe 4 degrees off track. (If you've only drawn 10-degree lines on one side of your planned track, but you are off track on the other side, you can visually see where the mirror image of your 10-degree line is.)
Now, to get back on track, turn right by double the track error; in this case, your track error is 4 degrees, so turn right by 8 degrees, onto a new heading of 052.
It's taken you 7 minutes of getting off track before you made this correction, so it's going to take another 7 minutes to get back on track. Therefore, once your stopwatch shows you've been flying for 14 minutes total, you should be back on track.
If you were to turn back onto your original heading of 044 now, you would start going off track again. (The wind was such that you went off track using this heading before, so unless the wind has changed in the last few minutes there's no reason you won't go off track on this heading again.) So, instead of removing all of your correction and going back to your original heading, remove just half of the 8 degrees of correction that you added - this will give you a new heading of 048, which should be good right the way to your destination or turning point.
Of course, you should also note down any heading changes on your plog. So the notes on your plog will read something like: "Time 7, hdg 052", "Time 14, hdg 048".
Like I said, far easier to explain with pictures than words, so I hope what I've written makes sense. Also bear in mind that there are many many other ways of doing this, so speak to your instructor and to other pilots, and pick a method you like.
FFF
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