Basics:

Tablature:

If you are not so familiar with tablature, here is a good way to start you up!

some extra information on the right hand fingers used:
T = Thumb
1 = Index finger
2 = Middle finger
3 = Ring finger

Simple Basic Strum:

Just count from 1 to 4 over and over again.
On 3 strum down your middle- and ringfinger over strings 1 to 4.
On 4 pluck the 5th string with your thumb

Basic Strum:

Just count from 1 to 4 over and over again.
On 1 pluck up the 2nd string with your index finger.
On 3 strum down your middle- and ringfinger over strings 1 to 4.
On 4 pluck the 5th string with your thumb.

Hammering on:

On 1 pluck up the 1st string with your index finger.
On 2 hammer on the 2nd string with the middle finger of your LEFT hand in position 3.
On 3 strum down your middle- and ringfinger over strings 1 to 4.
On 4 pluck the 5th string with your thumb.

Hammering on - pulling off:

The right hand is doing a simple basic strum.
On 1 the middle finger of the LEFT hand hammers on the 3th string in position 2.
On 2 the middle finger of the LEFT hand sounds the 3th string by pulling off and releases position 2.

All together now...

This example shows the combination of all learned techniques till now. It is the intro of Derroll's song called "The Skunk" as found on “Along the way”
(Derroll played it using drop thumbing but it suits us now to play it with the untill now known techniques!)

Hammering on - brush off:

By Golly, isn't this something! This is the essential trick I wasn't able to find (see intro) Saying it with Derroll's words: "I was sitting by the stove with my shoes off fooling around on the banjo" and there it was, the technique I never saw by any other banjo picker, as far as I know. This must definitely be Derroll's own contribution to the universal banjo techniques. Doing a normal "hammering on - pulling off" the pulled off note is always lower than the hammered one because we stay on the same string. Not so with Derroll! Here the pulled off note is higher! The whole trick is to hammer on a string and then brush down over the next higher string with the same finger. Sounds easy but needs some time to become right. So here we go:

On 1 the middle finger of the LEFT hand hammers on the 4th string in position 2.
On 2 the middle finger of the LEFT hand brushes down over the 3th open string.
Then the right hand makes the simple basic strum...

If you want to master the banjo in Derroll's style, this trick is a must to learn. He used it ever since his first recordings and is essential for his style. You will not find this technique yet in the songs-tabs. I hope to correct this in the upcoming ones. Anyway you can replace most of the hammer-ons pull-offs with this new find.

Double thumbing:

A different way of picking... The thumb plays the melody, alternating with the fifth string. The middle finger plays the first string.

Drop thumbing:

Unlike double thumbing, the thumb plays on the 2dn and 4th time like we are used to in the basic strum. The middlefinger plays the melody-strings while drop thumbing. The thumb drops to the 2nd or 3th string on the 2nd time to fill in with an extra note. This is exactly the same way drop thumbing is used in the old clawhammer style. Combining all the above shown techniques gives you a pretty close idea of Derroll’s way of playing...
Sample of “I ain't got no home” as found in Patrick Ferryn's Movie ‘I was born in Portland Town’.

Walz tempo:

A banjo can walz too ...
Just count from 1 to 6 over and over again.
On 1 pluck up the 2nd string with your index finger.
On 3 strum down your middle- and ringfinger over strings 1 to 4.
On 4 pluck the 5th string with your thumb.
On 5 strum down your middle- and ringfinger over strings 1 to 4.
On 6 pluck the 5th string with your thumb.

Some thoughts

The sequence of the shown basic steps is, as I believe, the same as Derroll’s own path to mastering the banjo. His first recordings show a lot of basic strum, often played very fast, with hammering on and pulling off. Later on he is experimenting with single notes and double thumbing to get more melodic phrases. Finally, ending up with drop thumbing, he gets this fantastic mix of all the above in his very own style. It took me a very long time to find out where all these extra notes came from, untill I tried drop thumbing. I believe this is the key to his technique, basic strum, hammer on, pulling off combined with the drop thumb. Fooling around on the internet I found the next photograph (sorry, don’t know the owner), where Derroll reveals his “secret”. This is what it says (as good as I can read it!)

try and get the thumb leed off so that you interchange with first finger leed working both with pull off ‘n hammer – yours amigo – me -> Derrollsky Adamskov the great russian composer ”

Derroll says he uses his first finger, while I am using the middle finger. Up to you to decide what suits you best!

Another approach of the same basic techniques is given by Pete Seeger.

Maybe good old Pete can help you out!