Also I remember a recent post where someone posted a screen shot of their map with great early game finds. However I can't seem to find it?? Anyone have the date/link to that post?
You might be talking about mine.
When I start a new world, my general process is this:
1. Find a biome above y80, the higher the better. I prefer green hills just because I like grass, but red rock mountains, extreme hills, or anything else mountainous functions similarly.
2. Dig a 1x2 tunnel at (8,8-9) straight down until hit ore or y5. I do this every chunk (though realistically every 2 chunks is probably more efficient) until I find something. As long as it isn't something obnoxious like a galena vein, I dig a + shape horizontally to find all the chunks that vein exists in. The huge majority of the vein should be in a 3x3 chunk square with density highest in the center.
3. Now that I have my grid centered, I dig 1x2 shafts every 3 chunks. Because I'm starting at high y levels most shafts I dig result in something, even if it's the 30th magnetite vein or whatever. If you don't mind hitting blanks frequently (especially with the spawn rate of tin buffed), you can start around sea level and still find many useful veins.
4. Make sacrifices to RNGesus hoping for what you're looking for.
As always, finding a specific vein early game is almost 100% luck. The nether can be a big help because vein hunting is much easier there, but since I need the overworld only veins anyway I don't worry too much about it.
Bonus tip: Before you go mining, find a fir tree. You'll need the wood for ladders.