First of firsts, making a doable plan is very important. Learning language is such a activity which needs to follow related plans strictly. Do you agree? If you have never followed your plans. What's the reason? If you have, then what're struggles during the process?
For me, I made a writing plan ever, but I didn't follow it strictly. I decided to write weekly. But after months, I found there was no space for ability improving. I means that I didn't find progressive in my writing process as before. So I had to stop the plan and found why.
It is common that there are many things that cannot be predicted for some plans.