Think about what you want before you start looking for a tutor.
What approach do you want? (mostly conversation? explicit grammar lessons? follow a textbook?...
Is it important to you that the teacher be a native speaker? Are you interested in a particular accent or dialect?
Is it important to you that the teacher have experience and/or qualifications?
Do you want a more traditional teacher? What sort of attitude do you expect from a teacher? Strict? Formal? Relaxed? Friendly? Flexible?
What type of things are you interested in outside of language learning? This is important because you speak with your language teacher a lot. It's easier if you have some common interests!
What are your general goals? Are you preparing for an exam? Are you traveling abroad for a short time? Are you planning on living or going to school in a country that speaks this language? Do you need to improve your professional language skills? Are you just learning for fun?
What are your specific goals? Do you want to be able to ask for directions while on vacation? Do you need to be able to write academic papers? Do you want to improve your ability to speak on the phone with coworkers? Think about the 4 main language skills: reading, writing, speaking and listening...what do you want to improve specifically? Which skill(s) and in what way?
Is it more important to you to measure an improvement in confidence or in grammar and vocabulary?
What resources do you want to use? Do you have a book you like to study with? What resources do you already have at home? Do you want recommendations? Do you want free resources? What type of resources interest you (authentic? Educational? audio? Video? articles? books?...)
What do YOU want to learn?
Do you want homework? What would you like to do for homework? Grammar exercises? Read an article? Listen to a podcast? Watch a movie or an episode from a Netflix series?
How many hours a week do you want to practice with a tutor?
How much do you want to spend per lesson?
Send messages to a few different tutors asking them about how they teach and telling them what you are looking for.
Look for a tutor using the filters (language, country, price, gender...)
Watch some introduction videos. Listen to see if they match your criteria.
Send messages to a few teachers and ask them questions about their teaching method and what they are like.
Tell them what your level is, what your goals are and what you want from lessons.
Eliminate any teachers that don't sound compatible with your goals and learning style
Do trial lessons
Pick a few teachers and schedule a trial lesson with each of them. Don't feel pressure to learn with the first tutor you meet with. Maybe you won't be compatible at all!
During the trial lesson, ask any questions you still have about classes with that teacher.
If you know you'll schedule more classes with them, let them know!
If you know you won't schedule classes with them...also let them know. If you feel uncomfortable telling them in the video chat, just send them a message later.
Make the most of class time
Have headphones with a microphone. It can be really distracting to hear the echo of your own voice on the other computer!
A few days before each lesson message the teacher any questions you have or topics you want to discuss.
Practice the language during the week by reading, writing, watching videos, using language exchange apps, etc.
Use class time to practice speaking as much as possible. In a one to one class, the student should be speaking in the target language at least half the class time.
Use mostly the target language, and ask the teacher to do the same.
Ask questions if you are confused, if you want an explicit explanation, if you want to change the way you are practicing in class...
The more you know what you want, the easier it is for a teacher to deliver that to you!