To make your goal measurable you need to determine the time you intend to achieve the goal and the result you want to accomplish in terms of an amount or quantity  For example if you want to lose weight you have to say how much weight you want to lose and the time, period or date you expect to lose it - "I want to lose 100kg by December 2023" for example. If the goal can't be attributed to a figure then use descriptions or characteristics. For example, if your goal is to look a certain way by December 2023 then characterise how you want to look. For example "I want to look more physically attractive by December 2023", characteristics - smooth skin, flat tummy, beautiful hair and clothes etc.

I recommend the short period should not exceed six months except really necessary. This period may vary with the goal so be flexible and realistic with it. If the goal is a long term goal that goes up to a year then divide the year into two, three or four short term periods which will give you short periods of six months, four months or three months respectively. If the goal is short term then you can divide it into days or weeks. 

These accomplishments are milestones and the more you accomplish your milestones the closer you get to achieving your goal. You may need to research and do some calculations to determine your milestones. Use the targets you set in the main goal and divide it by the number of shorter periods you created to know your short term target. For example if you want to save one million by the end of the year and you separated the year into four parts for this goal then you'll have to divide the one million by four to know how much you should save in the first three months of the year. 

I will advice you take into consideration your abilities and your reality when setting milestones. You may be more productive during certain periods and less productive in others so take the time to think and consider internal and external parameters in advance when setting your milestones. 

What do you need to do to achieve the milestone? Write them down as doable weekly or daily tasks. For example your main goal is to lose 100kg and your milestone is to lose 25kg in the next three months, then your tasks will be to workout three times a week, eat vegetables five times a week, drink 8 litters of water a day, etc.

Your tasks are the actions you need to take to accomplish the milestone you set.

When this is done, what is left is to take action and work on the tasks so that you can accomplish your milestones and achieve your dreams.