An often question I get from my students is: How do I stop thinking in Spanish?
Let me tell you with practice, effort, but chiefly, interest.
There are methods you might have heard of, either it is music, tv shows, movies or the like. These things are right, but they are the tip of the iceberg.
To start thinking in English is necessary to immerse oneself in the language. But not too fast, one step at a time. Going too fast could cause you annoyance and boredom.
Take the time to watch a movie or a tv series in their original language with subtitles: Many people dislike reading subtitles because they find it boring or distracting. When you begin to immerse, first, you must adapt your hearing to new sounds, not the words yet, just sounds. As you learn English, you will remove the subtitles.
Listening to music is a great choice, too. But be careful, music in English is full of idioms, or grammatically incorrect expressions that could confuse you. That is to say, when you are beginning to learn English, just try to adapt your hearing to the sounds.
Setting your browser and other devices in English is also a good idea.
Get an English-to-English dictionary: It is very helpful. The way we learn the meaning of words in Spanish is through reading a dictionary. The same happens in English. Using a dictionary gives you a new perspective to understand the meaning of words.
Label things in your house: You can label your furniture, kitchen supplies, laundry supplies, and whatever helps you learn these words since you add an image in your mind of those words.
Record yourself or talk to yourself speaking in English: Some people think it is kind of silly, but it helps a lot. Do not pay attention to people saying it is silly. You are learning something, and it is your process. Listen to your voice, the way you pronounce words, and notice which ones are easy for you and which ones are not.
Also, it is good if you practice stressing words and intonation. Questions and expressions, and even suggestions have different intonations in each language.
Write in English things like the supermarket lists, an errands list, your chores, or anything you like.
Find friends interested in learning English. Nothing like a group of friends to improve the learning process. In constructivism, the students develop their knowledge, and friends ease the process.
Read English materials: You can start from easy things like magazines and instructions to reading an entire book (don't forget your English-to-English dictionary)