A common question, asked by post beginners after learning how to open the game, is what they should do next. Here I believe there are four most basic factors which can help you to find reasonable way to deal with the situation.
1) Look for tactics by eyeing for checks, captures and threats. Most of the beginners’ chess games feature missed tactical opportunities, and mainly due to double attacks and pins.
2) Mobility is perhaps the most basic and important concept ignored by beginners. If your pieces cover more squares in general they are more mobile. You can do it by centralizing them. Try to trade your passive pieces (less mobile ones) for your opponent’s active ones. I think that difficult concepts like space, open lines, outposts, piece improvement or even the pawn structure are based around mobility.
3) Find the target and attack. Finding a target is the most difficult thing for them and us as it has direct relation to our overall chess knowledge. It is also at the core of formulating a plan.
4) King safety is an area where there’s nothing new that I can add. The game ends with checkmate so do not try getting any kind of advantage by putting your king into danger.
Did I miss something? Please do comment here.