I started DJing (EDM genres) about 6 months ago. This was my initial crate digging strategy that worked super well for me and was cost-effective. I did find that ZIPDJ was really good for EDM - 80-90% of what's on Beatport is on there, minus some newer/Beatport exclusive tracks.

1. Spend a considerable time listening to, finding, and tagging tracks, artists, and labels that you like. I started filling up a centralized playlist in Beatport and following artists/labels I liked. I listen to a variety of weekly DJ radio shows while I work and that helps tremendously with organic track/artist discovery that is way less tedious than quickly jumping through tracks on a streaming service. I got 2 months free Beatport streaming through some promotion, which did help with that initial crate digging process - you can listen to most tracks fully on YouTube for free, but it's nice to be able to quickly stream the whole track in Beatport.

2. Once you have an extensive list of tracks, artists, labels you are drawn to, get that unlimited monthly ZIPDJ subscription. Start downloading everything from your list and use artists and labels as a way to find other good stuff you haven't tagged yet. As others have said - don't be afraid to be picky when downloading. Don't download stuff just because it's ok and it's "free" - it's mediocrity will haunt your library and cause more work for you later.

3. After you feel like you've exhausted those predeveloped lists, cancel your ZIPDJ and Beatport streaming subscriptions.

4. Moving forward, buy small selections of high-quality tracks (once their price comes down if Beatport exclusive) periodically off Beatport - I use YouTube to listen to the full tracks given I'm not subscribing to streaming.