I think you partially answered your question. The main fact that you can "...execute tactics now without thinking..." is definitely a good start. Also that fact that you said, it "feels right" is also a good start although you don't really want to play a tactic just because it "feels right".
Information on tactics can be found from Louis Holtzhausen
site at http://www.chess-strategies-tactics.com/chess-tactics. Here is some information from that site:
Understanding why you would do a particular tactic can be made simple by the definition:
A Chess tactic is a move or a combination of moves whereby you force
an advantage. The advantage is usually to win material but it could
also be to achieve a positional advantage.
I think the fact that you said you can make tactical moves without thinking much means that you have improved your chess tactical awareness.
You can solve 1000's of tactical puzzles, but with no overall view of the specific skills you are trying to improve, solving them is not as effective. The 3 main focus areas of training chess tactics skill are:
1. Tactical patterns(how is the tactic executed)
2. Tactical themes(which elements of the position made the tactics possible)
3. Tactical awareness(knowing when to search for a tactical combination)
I think for each tactics puzzle that you do, before you do the next puzzle you must have a deep understanding of 1) themes
and 2) patterns
that made the tactics possible in the puzzle.
See if you can figure out which aspects of the position actually made the combination possible. This style of tactics training will hone your "tactical awareness".
Here are tactical themes and patterns that you should be familiar with.
You can find many of these themes on chess tempos website here
Fork or double attack
Pins and skewers
Sacrifice
Discovered attack
Deflection (or distraction)
Double check
Counter-attack
Hanging (undefended) piece
Exposed king
In-between move
Trapped piece
Clearance – Opening a critical square, file or diagonal
Blocking – blocking a critical file or diagonal
Advanced pawn
Attraction
Zugzwang
X-ray attack
Weak back rank
Removing the defender
Overloading a defender
Simplification into a winning endgame
Indirect defense
Domination in chess
Here are checkmate patterns you should be familiar with.
Checkmate pattern details can be found here.
Back Rank checkmate
Lolli’s checkmate
Epaulettes checkmate
Shepherd’s checkmate
Fool’s checkmate (fool’s mate or 2-move checkmate)
Scholar’s checkmate ( or 4-move checkmate)
Two Rooks checkmate
Mayet’s checkmate
Smothered checkmate
Anderssen’s checkmate
Pillsbury’s checkmate
The Arabian checkmate
Legal’s checkmate
Anastacia’s checkmate
Greco’s checkmate
Gueridon’s checkmate
Blackburne’s checkmate
Boden’s checkmate
Damiano’s checkmate
Understanding the tactical themes is useful… but training your mind to recognize the theme instantly and apply it in your game is only possible once you have turned your understanding into a skill. So how do you turn your understanding into a skill? Practice, practice, practice. Practice till you can apply your understanding almost without thinking.
Even if you find the content on these chess tactics themes and patterns obvious – it won’t do any harm to go over it again. It is vital to make this knowledge your second nature. It is better to understand a few patterns deeply than to understand many patterns superficially. Patterns you understand deeply will be much easier to apply!
Here are some tactical articles that will help you with tactics in the middle game:
http://www.kenilworthchessclub.org/links/middlegame.html