It may not come as a surprise, but if you want to speak well a language you must simply do that: speak!
You’re not going to learn a language by just listening to it and studying its grammar and words. Well, you may be able to read it, but speak?
Nowadays it’s easy to find speakers of any language online, either native speakers or language learners just as you. That’s wonderful and you could start some interesting conversations with them.
Speak to yourself
Nevertheless, at times it is not possible or we still feel very uncomfortable to speak to other people. In that case: speak to yourself! You can do this whenerver you want to, it’s fopr free and you won’t probably not laugh at yourself!
Imitate cool speakers
Why not taking this to the next level? Find some recordings of speakers whose pronunciation or way of speaking is attractive and imitate them! Yes, word by word, getting their intonation and sentence stress right and even their gestures and expressions. Even if you do not yet understand what they are saying. Do this in front of the mirror, records yourself (video and/or audio) and compare the result. What do you need to improve? And then: improve!
Learn like children do
Doing this you do what children are doing when learning their mother tongue. Kids normally doesn’t speak their first words up to the age of 1 and it’s not until 2 or 3 years when they start creating their first very short sentences. That is 3 years of listening and imitating! However, as adults we barely take this time (and we don’t need it, as our speaking muscles are already completely developed), but by spending some weeks or even months simply listening and repeating can really boost your pronunciation and thus self confidence!
Bonus: read out loud
Another speaking tip is reading aloud. Take an easy book or any written stuff that’s appealing to you and read it aloud (again, Internet is a wonderful source). In order to have some control over your progress, record yourself and observe your improvement over days, weeks and months. Doing this you don’t only work on your pronunciation, but also get some new vocabulary and interiorise frequent grammatical structures.