So you have had French in high school or college… but that is many years ago and you have never spoken French since!! Your French is badly rusty BUT you still know what you learnt. You just need to get it back and keep practicing to maintain your knowledge and progress.
You can start by reviewing your old notes, acquiring a review manual/tapes and immerse yourself again into the language. Very soon, vocabulary will come back, your ears will get used to the sounds and all the tricky grammar rules will make more sense.
A trip to a Francophone region of the world would also help you getting confident. You will realize you know more French than what you want to believe. Being confident is an important step for advancing to a fluent level.
Your challenge is then to keep acquiring knowledge and to ease your communication to become fluent in French.
Being able to practice with a French native tutor is very helpful and gives you the additional support you need to keep your French alive and to keep progressing.