Goal setting is an incredibly powerful tool for increasing your knowledge and expertise. You may have heard of SMART goals, which is a technique for setting goals that makes them highly specific, which can be especially important for setting achievable goals and establishing expectations for yourself which will make it more difficult to procrastinate. SMART stands for Specific Measureable Attainable Relevant and Time-based. In order to create goals that accomplish all of these things you need to identify a Specific thing you want to accomplish, define a way to Measure your progress and when you have accomplished the goal, ensure that the goal is Attainable and as such within the Timeframe you establish and the goal should be Relevant to you, your values, and your objectives. If you aren't interested in your goal you are unlikely to achieve it.
If you aren't choosing to learn something, but rather are required to either for your family, your school, or your work, getting yourself excited about the subject, the language, or the skill can make it much easier to engage with. Find something about the subject to love, something about the language that excites you and becomes passionate about that thing so that you can have an easier time setting goals that will be invigorating to meet and that you will be motivated to achieve.
Seek to spend a set amount of time studying the language each day during dedicated studying time, whether this is with a course from the Online Language Courses, a textbook, or through other means, and focus on taking notes and focusing on remembering what is being taught.
My goal for learning Italian was to complete a set amount of curriculum from the Future Learn Italian for Beginners course and spend 20 minutes on Duolingo. I also created flashcards for myself on Anki that I reviewed every day and drew concept maps to make deeper connections between vocabulary words and phrases. Since I was just beginning to learn I needed the structure of those courses to guide what vocabulary was important and that I should be seeking to learn but as I progressed I started incorporating more independent study methods including reading novels and annotating them with my own notes, questions about the words and meaning of challenging phrases. I began writing journal entries in the language I sought to understand, and I used the "Language Learning with Netflix" Chrome extension to hear new vocabulary words and phrases that I could then add into my Anki flashcards.
You should also look to engage in the language in less focused ways that are geared towards experiencing the language. This can be through listening to music in the intended language, watching movies or TV shows without your native language's subtitles, or having a conversation in the language. See if you pick up on anything specific, but don't try to take notes.
When you begin learning a language you'll need to invest more time in order to see progress. Your daily goals might look like 20 minutes of dedicated structured study either from a course, an app, or if you're on your own try to conjugate a verb every day, write a list of 10-30 vocabulary words and make flashcards for them and revise vocabulary words from previous days trying to focus on learning words that are relevant to a specific topic.
While there are any number of topics within a language, you should begin with the alphabet and numeral system if they are different than your native language. From there seek to learn pronouns, distinctions for gender and age such as man, woman, boy, girl, old, and young. These can be important when addressing people especially in cultural contexts where elders are greeted with words that convey a higher level of respect. After that, learn articles such as "the," "a," and "an," "to be" words such as "am," "is," and "was," and possession words such as "have." You should then learn how to ask questions, "who," "what," "when," "where," "why," and "how." The next few subjects vary by course and can be interchanged but learn colors, size, directions, conversational greetings, family relations, animal names, locations, food, and drink.
Two phrases you should seek to learn early on are "How do you say ___?" and "What does ___ mean?" These can be used when trying to learn from someone who knows more than you, such as "Come si dice apple?" which means "How do you say apple?" in Italian or "Cosa significa sfogliatelle?" which means "What does sfogliatelle mean?" in Italian. Sfogliatelle is a cream-filled pastry that is decadent and native to Campania near Naples.
Once you've become more fluent in the language you should adjust what you're doing for your dedicated study time so that it is something that you are still interested in focusing on and continues to challenge you. If you can read a children's novel, move on to something more advanced, watch a television show or movie that's intended for adults that are native to the language.
A couple of times a week, work on reading an article or a few pages from a book. Write something in your target language. Listen to a podcast or a book in your target language. Watch a movie or a television show. Listen to music in your target language. While listening to something, repeat what you hear. Talk to yourself, your friends, your plants, or a tutor in the target language.
Write something larger in your target language such as an essay, a rant, an in-depth description, or a review about something that's on your mind. You're not turning this in, just try to write about something that interests you.
When looking at setting long-term goals you can test your fluency for many languages using the CEFR Proficiency tests which have levels for proficiency and fluency ranging from A1 to C2. You could also seek to set a time spent practicing goal or a goal based on being able to adequately communicate about a subject you're interested in within the given language. Some of these long-term goals are easier than others to meet and it's important to decide what kinds of goals you want to set for yourself.