A SMART goal is an acronym which stands for Specific, Measurable, Achievable, Realistic and Time-bound. You will find some variations on what the letters stand for, but the principles are very much the same, and they are most noticeable when they are not there.
For example, many goals are not specific enough. Whilst "I want to earn a living wage whilst managing a family life at home" is a laudable goal, it is not very specific. If it is not specific enough, then you will not know if you are on target to achieve it, and you will either work too hard to make more money than you need at the expense of family life, or you may not earn enough to pay the bills.
A key part of having a specific goal is the ability to measure your progress towards achieving it. Supposing you need $2500 a month to pay the monthly bills, then you can measure your earnings as progress towards that income target.
Goals must be achievable and realistic. Is the money you need to earn possible to achieve within the period available? If you cannot earn around $100 a day from what you do, then you will not be able to reach your monthly target. Similarly, you need to be realistic about what can be achieved in your circumstances. Going to work in an office may seem to be inconvenient but it has many less distractions than home. How long is your working day at home, if you have to get the kids off to school, and then get all your work done before they come home again?
Finally, goals need to be time bound. You need to define the time period over which you want to achieve your goals.