There are many tactics so it's a good question. Breaking it down into manageable chunks is a good way to organise learning them. A good book that teaches tactics is Chess Tactics for Students by John Bain. It teaches Pins, Back Rank Combinations, Knight Forks, Other Forks, Discovered Checks, Discovered Attacks, Double Checks (cant be blocked king must move), Skewers, Promoting Pawns, Removing the Defender, Zugzwang and stalemate. This is a good starting set. Keeping adding to it as you become more confident with them.
Training tactics
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I think strategy and planning are often confused. Strategies are quite broad and conceptual. Planning is the execution of strategy. As a beginner you probably only need to know a few strategies and should work more on understanding short and medium term planning (where to put your pieces). Some simple strategies are controlling the centre in the opening, trading down when you are ahead in material. To help with planning, start learning about positional ideas such as open files, weak squares, knight outposts, weak pawns, etc.
Daniel, I should have looked at your rating before messaging. Have a look at Simplify Chess (google it). They have a lot of good material on pawn structures and medium term planning. You may find it helpful. It helped me better understand how an opening can flow into a middlegame.
Thanks a lot Mark. I'll be sure to check all of it out 
I'm fairly new to learning chess, but am benefiting fairly well from (a) doing a daily puzzle or two here on chess dot com, and (b) working my way through the book Progressive Tactics: 1002 Progressively Challenging Chess Tactics by Couture.
Puzzle rush is great because it starts off easy, so you can attempt the first few ones.
You'll notice some patterns: back rank tactics, forks and undefended pieces are the most important tactics to learn at a beginner level.
Once you get more advanced: exploiting pins, diversion and clearance sacrifice tactics are important.
In what order would you recommend training tactics? I find that doing random ones isn't helping me improve as much as maybe focusing on a few kinds of tactics at a time. Also, what would you recommend to train strategy? Sometimes I find myself a bit at a loss when it comes to choosing the best move, especially when it comes to pawns (take the pawn? push it? how will it affect my position in the long term?)