Classical / literary chinese is a fuzzy language, and there are subtle differences amongst dynasties, authors. Using dictionaries to learn how to write, is, well, side way (歧路).
Understanding particles (虛字) and "pausing at the end of a phrase or sentence" (句讀) are crucial. After managing these two skills, one could write naturally.
For particles (虛字), the internet archive has these free materials:
chinesische grammatik, this one is in german, correlated with 經傳釋詞.
Then, the internet archive also has the imperial collection of four (四庫全書), in which all text are not punctuated, good for 句讀. 四庫全書
Lastly, learn to read and write classical / literary Chinese in the traditional script.