Can we decompose a schema into BCNF when it is not even in 1NF Given a schema r(A,B,C,D,E,F) and  a set of functional dependencies


A --> BCD 
BC --> DE
B --> D
D --> A


As we can see the schema is not even in 1NF as can be read here, now the question is can we directly decompose the schema into 3NF forms or we have to first bring it to 1NF.

If we directly decompose, it will be as follows

Since A --> BCD is not a trivial relation and A is not a primary the relation breaks up into 

r1(A,B,C,D) and r2(A,E,F)
and then we again break r2 because r1 is now in 3NF but not r2
then we get r1(A,B,C,D) r2(A,E) and r3(F)

But this does not make sense because we must first bring the relation into 1NF first and then decompose it, by doing that we can get two schemas r1(A,B,C,D,E) and r2(F). By this we see that r1 is now in BCNF and we need not further decompose it and r2 is also in BCNF.
Always hit it at first shot? It is not guaranteed. You apply normalization rules to remove anomalies from relations. Relations rise to a more normal form. You observe for anomalies again and if there are anomalies apply rules again. It is possible to reach most normal form possible for the relation at first move (as you know there is a limit for normalization of any relation. Ron Fagin showed that it is often impossible to achieve DKNF form) but not always. Ron Fagin's paper may help.