Meditation is always powerful for me. Reading books, talking with friends, watching movies, listening to music, writing and going to parties also help me. Sometimes there is so much pressure on doing something and it discourages, so it's good to take a break and do something different.

In addition to the great advises, mentioned above, I think you should surround yourself by optimistic people. Moreover, remind yourself by your goal and how important it is or how you exaggerated a lot of efforts to achieve it. Also, you may take a break in order to renew your energy.

Motivation and impetus come from interests,  If you get something interested you, You can enjoy it and go into it deeply. My first hobby is radio, It accompanyed me from my childhood time to now; and photography; and violin... Although I spent much hard time with them, but They give me so much joy! let me feel my life is full of valuable contents. So all motivation come from love, love to sciences and arts ...

 Find a friend or  find something interesting book or movie.  To know any foreighn language is always nice because it can learn people think differently. Comparing languages is also very nice . Ukrainan and Russian are related to English- all derived from Protoindoeuropean   language and even the languages are not understandable they share same roots 

i want to learn english conversation can you join me