When I play chess I always take one of two roads which both lead to defeat.
Either I play very carefully, leaving my opponent open to all of the attacking. With carefully I mean I only move important pieces to spots which are defended.
Or I play too recklessly which makes me lose important pieces to the stupidest of decisions. Seriously, I lost tons of queens to spots which were very clearly defended.
Either way I always lose. So:
Does anyone know of: tactics, videos, rule of thumbs, anything. Which can help to find a good balance?
Also: When should you start strategising about check-mating the king?
For sure: there are some pretty good rules of thumb for when to attack.
Generally you want to develop your pieces first. What does that mean? It means you want to get your pieces on squares that aren’t the row closest to you.
Often players will start attacking without having moved some of their pieces. This is often a mistake. Think of it this way: your opponent has all their pieces near their king to begin with, so automatically has more defenders than you have attackers. You need to get yours out to have a decent chance of delivering a checkmate.
There’s also a good rule of thumb in terms of the order you get them out in. Major pieces (queen and rook) are worth more than minor pieces (knight and bishop). So if you get your queen out early on a square it can be attacked, that leaves it vulnerable to being chased round the board, letting your opponent develop their pieces while attacking your queen. All of a sudden your opponent has all their minor pieces out, while all you’ve done is shuffle your queen.
Another key piece of advice is to control the centre of the board. A piece in the centre is much more powerful and controls more squares. Think of it like the high ground on a battlefield. In general in the opening you want to control this centre with your pawns, and minor pieces (knights and bishops) one way or another
So: in terms of the order you want to do things, most often you want to play a central pawn forward, develop your knights, then your bishops, then castle (keeping your king safe and bringing a rook towards the centre), then start looking for where you can develop your queen to start generating pressure.
The final piece of advice I’ll give is that tactics (checkmate or being able to take your opponent’s pieces) stems from having a good position: that is, having your pieces on squares where they are eyeing up the enemy position. You want to put your opponent under pressure, at which point tactics will start to appear to you.
If you want further resources, there’s a wealth of chess on YouTube. I’d highly recommend Daniel Naroditsky’s speedruns (starting at the beginning, in your case). He plays opponents of increasing skill levels over the course of many videos, so the early videos explain the basics of how to play chess according to sensible principles. Good luck, and have fun!