Leitrim-Roscommon

Hi.
I am just starting to trace my Family history.
They are originally from Roscommon ( Ballyhaunis,Tully,Cloondart, Areas)
So far i have Father John born around 1925 he had 1 sister Mary and 4 brothers Thomas,Bill,Frank & Joe.

Grandfather Thomas Grandmother Mary (Flanigan )
G/Grandfather Thomas not sure G/Grandmother.

I need help tracing family of Thomas (Uncle)also any and all relatives of grandparents etc.

Any suggestions on where to start would be appreciated.

Hi Ed

thanks for your help and suggestions.
I will update the site when i get any further information

I've found a bit more information about my family
G/father & G/mother both buried in Kilruddane Cemetry
Gfather Thomas Born about 1884
Gmother Mary Flanigan Born about 1890
GGfather & GGmother no ideas yet of age/birth/death
Also found out i had Uncle i never knew existed, name Thomas born about 1913.No current members of Family no anything about him.
Anybody got any suggestions where i could start looking?