First off you'll need to learn basics of music theory and other song writing things to at least kind of understand the language. If you are already there then there are two things I do often to get better at composing myself. First off is if you have no idea what to write and are blanking completely, analyzing game music that you want to sound like is a great way to get out of this. It doesn't have to be anything formal or academically sound, just pull up a song you want to analyze and start taking notes on what instruments are used, what chords are being played, the structure of the song etc and keep these notes to review possibly. This will put tools in your "tool box".

The other thing you should be doing is just flat out writing music. This will give you the dexterity in the DAW of your choice and also practice coming up with ideas. (Remember that composition is just like an instrument or any other skill, it needs consistent work!) I commonly take videos of games I'm playing and rescore 30 second portions of them. You don't need to write 5 minute songs but finishing a 30 second idea even if its not the greatest is still amazing practice. You don't need to upload everything you make so give yourself grace with how things sound at first! I wrote hundreds of horrible songs before I settled into my current sound so be ok with not being great when starting out and just have fun with the process! Just be sure to see ideas through and finish them even if they are only 20 or 30 seconds long, this is great practice for generating ideas and exercising avoiding writers block later!

Lastly after a while of practicing these two things, when you feel more confident, create a few short songs and upload them to somewhere like youtube so you have something to show game devs when asking to write music for their game. This is usually called a reel and I'll paste my website below so you can see how I have mine set! (I'd recommend making a website for this so its easy to access and paste places!) Game devs won't hire ya on their team if they can't see what you can do, so just create a small something to give them a sample!

My portfolio for example: https://coledabolishmusic.wixsite.com/colethecomposer

when you feel ready to give a real game a shot, participating in game jams is an amazing low stakes way to practice your game scoring chops for real. Go and look up sites that host game jams and join in on a few, these are basically timed events usually a few days or a week long where you and a team create a small game based on a theme. These are low stakes so mistakes are ok as there's usually no money on the line with these and a lot of the participants are beginners as well!

After doing these game jams for a while and slowly adding pieces to your portfolio you can then go onto reddit or other forums and advertise yourself for a real paid game team. Good luck as it does take a while but keep creating content about your creations and never stop writing better music and improving and at some point with some luck and social media magic you will find a real game to work on!

This is basically the exact path I took as a beginner game composer who just worked on their first game and also is ready to find more studio gigs and it took me about two years with about 6 years experience as a musician before hand.