Notes

Beginner learning phase:
Opening principles - Developing pieces towards the center, taking control of the center with pawns, getting your king to safety as soon as possible (usually/preferably done by castling), don't bring your queen out early unless for good reason, don't move the same piece multiple times due to the loss of what is referred to as tempo (Unless you know it is absolutely justified)

common mistakes - making one move threats without calculating or thinking of what the responses could be (such as giving a check when the piece giving check can be blocked and attacked at the same time or when you make a threat but don't realize that you made a blunder {loss of material or given up the advantage to the other player}), pushing pawns in front of the king without a good reason to. These moves can weaken the kings safety and king safety in chess is very important. Making random moves without a reason as to why they are played. In chess every move needs to have some type of reason behind them (doesn't necessarily have to always be calculated, just have some type of idea behind a move you're making. This improves your games a lot)