There are trillions of electrons crowded in every millimeter length of wire in a circuit. Each electron moves frantically in random directions at thousands of miles per hour even while a wire is not connected to a circuit. The electrons don't get very far before colliding with neighboring electrons and the atoms of the wire. Imagine the floor of the New York Stock Exchange, a densely crowded floor with people moving from table to table in every direction.
When a circuit is closed, the electrons all begin to move at once in a particular direction at the same time that they are moving frantically in random directions. As a result, the electrons drift very slowly along the circuit length at only millimeters per minute, even though trillions of them are moving together. There are so many electrons packed into a wire that slow progress still means huge numbers going by a given point every second. Imagine the floor of the New York Stock Exchange tipped at a steep angle, such that the occupants end up drifting toward one exit as they attempt to travel to the tables of their choice through the crowd.
As electrons speed up under the influence of battery voltage, they quickly bang into obstacles and lose whatever energy they gained. The obstacles are the fixed atoms in the resistor, which respond by vibrating. The vibration energy is what we think of as heat. Imagine the tipped floor of the New York Stock Exchange with many tables bolted to the floor; as the occupants thrash around and drift downhill, they keep whacking into the tables in their way. The more tables, or the bigger the tables are, the longer it takes for the people to drift to the exit doors.
Long, thin resistors limit current the most. It's all a matter of how many obstacles block how many electrons trying to get through at once. Imagine the Stock Exchange floor is now a long, narrow corridor with the same table density: people will get more whacks per trip because a long corridor has more tables to hit, and fewer people will get past a given point per minute since the corridor width can only accomodate a few people at a time.