Step 1 make lists of the most common words.
Each list should be around 30 words, if you do more it will be harder to concentrate and you will lose motivation.
So write down till hsk4
Every day review one list of words, dont skip days or atleast not more than 1 day a week.
If you know the words characters well.
Step 2 build up the vocabulary with words that have your interest and some words from hsk 4.
10 hsk 4 words and 20 words about your interest.
Again helps to motivate, how to build up your vocabulary? Can with watching a show or reading a childrens book.
I have now around 321 lists of words. Read +100 stories books in chinese. Sadly only watched +10 shows in chinese. I should motivate myself to do so but i like korean shows too much ha