One of the most basic yet important things to understand in a battle is the size of the battlefield.
Battlefield size is defined as the distance between the attacking and defending troops before the first movement of the battle.
Battlefield size is determined one of two ways,1) a default battlefield when no ranged troops are used by the attacker and also 2) by attackers greatest range if range troops are included.
Examples of these are if attacker sends 5k ssd with no other troops then the absence of range troops would cause the battlefield to be set at the default length.
Current testing places the default field length somewhere between 350 and 370 spaces.
If the attacker has max research the same March with 1 lightning cannon would increase to the range of the lightning cannon with max research. The base range of is 1600 and max research would add 50% to this distance(1600*1.5) for a battlefield length of 2400 spaces.
Other range troops can be used to vary battlefield length as needed, for instance, various levels of fire mirrors will create varying field size due to varied range.
Being aware of field size can give you an advantage by keeping opponents speed troops from crossing also knowing how to stay out of reach of lower level defending range.
Weapons calibration is the main factor that will affect troops range and there fore affect battlefield size so make sure to get that research up to par.
Have fun and enjoy