Where do you want to be with your English in the end? Make a specific objective: e.g. I want to be ready for the next level by passing the unit test in 12 weeks.
Are they measurable?
Can you measure your achievements? Re-do the level test after 12 weeks to see if your improvement can be seen.
Are they achievable?
Is what you are hoping to do achievable? Don't be too ambitious. Be honest - 12 weeks of study will improve your level only a realistic amount. Remember this.
Do you have enough time?
What time-frame are you considering? Set a clear time plan. e.g. I want to have achieved this in 12 weeks.
Are they realistic?
Are you being realistic? Again don't be too ambitious. Be honest with the time you have. Consider the other commitments in your life.
Motivation:
If you have motivation you can achieve anything. People have many motivations to study English; here are some (Try to remember them every time you feel a lack of motivation):
1. Better English often means a better job and higher salary.
2. Travel opportunities increase.
3. Most people's main second language is English. Knowing English yourself will allow you to speak and get to know a huge number of people.
4. Having a second language gives you a sense of pride and accomplishment.
5. Comparatively, English is not the most complex language in the world. There is no real case or gender system and our tense forms are quite simplistic. It is reasonably easy to learn.