Can't believe I missed such an obvious tactic

I completely missed 12. Bxh7 somehow. I had the right idea, but just completely in the wrong order. Luckily my opponent got very confused and blundered as well.

Any tips on curing my blindness to these tactics? I've done tons of tactics training but I still frequently miss these kinds of tactics.

It is a typical pattern: the bishop on d3, the knight absent from f6... From experience this is the first thought.

This is called Greek Gift Sacrifice and you can look up videos and examples on it. It's something that usually requires no calculation to understand whether it works or not, you just have to check for certain elements in position.

1.Bishop on d3-h7 diagonal.
2.A Knight that can go to g5. Usually on f3 but sometimes on h3 or e4.
3. Queen on d1 (or another square on the same diagonal towards enemy king)

These three elements should make you at least consider the possibility of Bxh7+. You still have to calculate concretely to see if it works.

5. A pawn on e5 (it is important to cover f3 to cut off the enemy King, and also ensures that there's no enemy Knight on f6.)
6. Bishop on c1 to protect g5 and potentially deliver discovered checks.

With these 5 pieces ready usually no calculation required. Just check for:

5. Your opponent is covering g5 square twice (usually with a queen on d8 and bishop on e7)
6. Enemy light squared bishop can't defend h7 after Ng5 Kg8 Qh5. This completely counters Greek Gift. However this Bishop is usually blocked in by the pawns in French Defense where Greek Gift most commonly occur.
7. Both enemy Knights shouldn't be able to go to f6. If they can, your opponent can sacrifice one of the knights to the e5 pawn and defend h7 with the other.
8. Open f file for the opponent can be slightly problematic.

And finally the additional factors that can strengthen your Greek Gift or make up for the pieces you're missing. When you feel like it's not working you can maybe set up one of these situations.

9. A pawn on h4.
10. Open f-file.
11. An additional knight that can go to g5. (works well against the point 5)

And in general, just having many pieces pointing towards the enemy King while your opponent having no defenders. In your game you have 4 pieces ready to strike and opponents pieces are stranded in Queen-side. This should make you think in the most aggressive ways and look for sacrifices.

As a side note, there's also a more patzerish way of setting up Greek Gift by playing h4 before castling, intention is to recapture after Bxg5 with hxg5 and open up your rook. This is another way to work around enemy Bishop on e7 which is the most common defender against Greek Gift.

You still have to practice or study the common continuations after Bxf7+ but once you get used to it ts you'll never miss this fun opportunity to sacrifice.