Let’s look at how these apply to language learning.
Specific
Goals must be clear and not too broad or vague. “Be able to speak German” might sound like a good goal, but what does that actually mean? Holding a basic 10 minute conversation is speaking German, having an depth academic discussion about global warming in German is something else entirely.
To stay motivated and see your progress you need to know when you have achieved your goals. To do this they must be measurable in some way.
Some people might find that setting a time target (study for 15 minutes a day) works better for them than a results target (learn 15 words a day). Use what works best for you.
Poor goal Improve your vocabulary.
Better goals
Learn 5 new words a day.
Spend 20 minutes a day learning new words.
Attainable
Setting goals that are too difficult will kill your motivation.
It’s good to push yourself a little, but you must realistically be able to reach your goals otherwise you’ll just feel defeated and lose interest.
Regularly hitting small milestones is the key to eventually conquering the language marathon.