Yes, you can do this.

I did it myself.

Here is a list of things that helped me:

1) A good book of verbs

2) A good book of pronouns and prepositions

3) The book "Fluent Forever" by Gabriel Wyner has the best system for learning a new language

4) Movies & TV shows in Spanish (to train your ears on the sound and the rhythm)

6) Practice speaking with someone every day, even if it is only for 15 minutes

7) Create your own projects that use the language

I am happy to answer questions about it.

You can try listening podcast that teaches Spanish

I don't know what your definition of fluent is. Fluent means different things to different people but it is definitely possible to learn on your own in addition to Italki to a high functional level. I would suggest also getting a conversation partner. You are able to find a conversation partner free although you have to be careful. There are some sites geared towards mutual conversation exchange but turn out to be just people looking for dates. I ended up restricting my search to other females and even with this some times men has masqueraded as females....which I don't understand why because as soon as I realize it's a male I will log off. I digress. It depends how you learn. For me I have to learn the grammar first so I spent alot of time working drills then from there learned vocabulary and idioms. I use text books alot but I also watch movies and changed the audio to spanish as well as the subtitles. If there was a book I was interested in reading, I'd buy the spanish version. If you find ways to incorporate the language into your daily life you will be able to learn it at a faster pace. You should get books and training materials geared towards the D.E.L.E. it will give you a good foundation although in your posted you hadn't mentioned that you were going to take the exam. Since it looks as though you are bilingual currently, can't you use the same methods?

I can help you if you want.

Hi Claudia! I learned Spanish withing 5 monthis and passed B1 exam after that. I learned with busuu platform - it is well organized. I can recommend it. I can recommend you these channels:

https://www.youtube.com/user/sgelele/playlists; https://1001reasonstolearnspanish.com/

Good luck!