How do you keep motivated?

Having small goals and achieving them one step at a time, create a pattern of success.

Having goal like "I want to be a millionaire" is not very helpful. How will you achieve this and in what time frame? (Because people do have this kind of goal is the reason that the Lottery is so popular.)

Set a small goal with a realistic timeframe:

I will sign up 10 affiliates in my first 3 months.
I will sign up 100 affiliates in my first year.
I will be making £100 a month within 6 months.
I will be making £200 a month by the end of my first year.

Once you've achieved this it's easy to go for more ambitious goals:

I will be making £500 a month by the end of my second year.

Then:

I will be making £2000 a month by the end of my third year.

So within 3 years you are making enough to really run your home business full time. Give up the day job.

Then it is time to set the really big goals, like Six Figure Income (and we all know where that came from), and go on from there.

Even the Great Wall of China was built one brick at a time.