Optimizing SQLite for servers
PRAGMA journal_mode = WAL;
PRAGMA busy_timeout = 5000;
PRAGMA synchronous = NORMAL;
PRAGMA cache_size = 1000000000;
PRAGMA foreign_keys = true;
PRAGMA temp_store = memory;
Source: https://kerkour.com/sqlite-for-servers
Other the well known "1 connection for writing, multiple for reading", see the IMMEDIATE transactions section.
Also see the following post: Distributed SQLite: Paradigm shift or hype?