The recommended way to improve tactics is to practice looking for them. ChessTempo is the best site to practice tactics. chess24 also has tactics training and has good videos. Lichess has tactics and one of the best playing sites. Youtube.com has too many chess videos to list them all.
There are some clues to look for to find tactics. An unprotected back rank, pieces which are on the same line, pieces which are a Knight fork away, and pieces which are unprotected. More advanced themes are overloaded piece, trapped pieces, and zwischenzug et al.
Alburt's 300 most important positions and Reinfeld's 1001 best checkmates are PGNs which you can download. Chess Hero is a program which will test you with these files (includes Reinfeld's pgn.)
Along with tactics, you will find attacking becomes easier.
spy-faith(2113) jonesmh(2052) lichess.org 3 0
Exploiting an overloaded Knight on c3.
1. e4 c5 2. d4 cxd4 3. c3 d3 4. c4 g6 5. Nc3 Bg7 6. Qxd3 Nc6 7. Bf4 d6 8. O-O-O Nf6 9. Bg3 O-O 10. f4 Qa5 11. Kb1 Nb4 12. Qd2 Nxe4 0-1
Unusual attack on the king.
[fen "r3rbk1/ppq2pp1/2n2n1p/2pp1P2/5P2/2PBB2P/PPQN2P1/R3R1K1 b - - 0 0"]
1...c4 2.Bf1 Rxe3 3. Rxe3 Bc5
With every piece protected, the attack broke through. A hard example of a weak square complex.
jonesmh(2080) kavookavala(2133) lichess.org 3 2
Exploiting uncoordinated pieces
1. f4 d5 2. e4 dxe4 3. Nc3 Bf5 4. Qe2 Nf6 5. Qb5+ Bd7 6. Qxb7 Bc6 7. Bb5 Bxb5 8. Nxb5 Qd5 9. Qc8+ 1-0
jonesmh(2079) nfc3000(2061) lichess.org 3 2
Overlooked Knight fork by both player.
1. e4 c5 2. Nf3 d6 3. d3 Nf6 4. g3 g6 5. Bg2 Bg7 6. O-O O-O 7. Nbd2 Nc6 8. a4 Bd7 9. Re1 a6 10. Nc4 Rb8 11. a5 Be6 12. e5 Bxc4 13. exf6 Bxf6 14. dxc4 Nxa5 15. Qd3 Qc7 16. Bd2 Nc6 17. c3 Ra8 18. Bh6 Rfb8 19. Qe2 Na5 20. Bg5 Bxg5 21. Nxg5 Re8 22. Rad1 Rab8 23. Qd3 b5 24. cxb5 axb5 25. b4 Nc4 26. Bd5 Ne5 27. Rxe5 dxe5 28. Bxf7+ Kg7 29. Bxe8 Rxe8 30. Ne6+ 1-0
These examples show that 2000 rated players miss simple tactics in blitz. The longer you play and/or solve tactical puzzles, the easier you will find the combinations..
(As I kept going back and forth to input the examples, I lost track of what I was saying many times. Hopefully I did not stray off topic too much and did provide helpful information.)