It is best to do it on paper so everything lines up.
2| 81
2 goes into 8 four times, so
4
2|81
8
Next, we ask how many times 2 goes into 1? You need to do every digit. 2 goes 0 times into 1 evenly.
40
2|81
80
------
0 1
Subtract the numbers. You now have a remainder of '1' since there are no more digits left to divide into, but I'll continue it by using a decimal point and adding a '0' to the bottom
40.
2|81
80
------
0 10
We see that 2 goes into 10 two times with no remainder, so we are done.
40.5
2|81
80
------
10
10
-------
0
Just keep practicing. Long division is the hardest thing in basic math, but you will get it with lots of practice.
