What is your native language? My first suggestion would be to do the groundwork for your academic writing in that language--build a structure, map out your analysis and argument, etc. Then, perhaps with the help of a native speaker, slowly work through a translation. The key is to build your skills in small steps!
As with other types of academic writing, there is a specific language that is appropriate in the psychology arena. Therefore, I would also be sensitive to this, and familiarize yourself with psychology literature and journals. This will give insight not only into language and style, but how psychology papers are structured.
If you would like to submit a piece of writing, I would be happy to take a look!
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