You should 100% follow the other advice in this thread first but be aware that some seeds can ♥♥♥♥ you over completely. Our first world as a group we spent days real world time trying to find enough swamp to mine iron. We eventually gave up and used the world checker and some console commands to try and find it, only to discover what swamp did exist was almost entirely under water. We recently restarted a new world server post mistlands and hit almost the exact same problem. ♥♥♥♥♥♥ luck on our part but we ended up just snagging a seed from reddit (without looking at it) that had several endorsements as being a good balance between exploring and resource availability