Blitz is the fast game with time for a move in 3-6 seconds. Some players believe that blitz impairs the playing abilities because of the small time for a move and this impacts the classic games negatively with more time for a move. But blitz can be useful and the ability to play blitz should help in the classic game.
Beginners rarely play in blitz, because they play weakly in the classic also and they think slowly. Among the strong players the blitz is spread since it takes less time and effort. Some good players do not play in the blitz of the fact that they are not able to think quickly. However the blitz advantage is associated with quick thinking to train and to improve the memory and concentration. This advantage gives the possibility in classic games to calculate more situations and to make fewer mistakes.
You need time to start playing good in blitz. First, the player must make moves as quickly as possible because he can lose the time for game. Then the player must learn to think in a blitz. During the large number of exercises you can learn to calculate several moves ahead in blitz.
You should try to bring the playing level in blitz as the level in classic game. Then you can play classic games rarely and spend your effort for blitz game to save your time for training.
Start position 4Х
Start position with four crossings (4X) is common among good players. 4X makes the game more interesting, because the situation in the field is more challenging. Both players have to attack and defend. 4X is profitable for players with better attack. Also in 4X (and in general, with increasing of the number of the crossings in game) to a stronger player becomes easier to win over the weak player.
In the 4X at the game beginning you should try to build your chains on the perimeter and to guide the opponent's chains to the center (figure 1). Some opponent's chains you must try to leave outside. Therefore you get the better position on the field. Firstly you should use your dots in 2-3 crossings. The rest will be used later. Then you can attack the opponent's weak position through the field center. It is difficult to capture all opponent's chains, so you should try to capture a chain with weakest position and then you should launch the defense.
Figure 1 - The example of chains position in 4X. The blue chains are constructed around the perimeter and they get a better position. The blue chains guide the red chains to the center
The game on territory
The game on territory is common among Polish players. Firstly you need to learn the rules of this game, because they are more complicated.
If you are playing worse than the opponent for the territory, but better by the usual rules, then you should choose the larger field size and you should try to increase quickly the number of crossings and to capture at least a few dots of the opponent. If you can't capture more dots of the opponent, then you should capture the territory and prevent an opponent to do it.
The game without landing
In the game rules are without the landing, then you should follow the recommendations of the game for the territory. However, in the game for the territory it is desirable to make large unfinished encirclements, but in the game without landing you should build houses with small size as it possible.
If your opponent has created a house of large size, then you shouldn't wait until the opponent divides it into small houses. You should put the dot in the large house to complete its encirclement. Using such techniques you will improve the game score in the long term.