A good strategy to follow when ordering phrases and clauses within a sentence is to place the most familiar information at the beginning of the sentence and the newest information at the end. Thus, information in the sentence will move from old to new, the old serving as a platform to support the new.
Anabolic steroids were used to rebuild the body weight of
concentration camp survivors [new] after they were developed
in the 1930s and gained recognition after World War II [old].
Anabolic steriods were developed in the 1930s but gained
recognition only after World War II [old], when they were used
to rebuild the body weight of concentration camp survivors [new].
--"Steroids," Compton's Encyclopedia
Sometimes the old information is in a main clause, and sometimes it is in a dependent clause. (For how to decide whether to put information in a main clause or in a dependent clause, see Important Information in Main Clause.) In either case, put the clause containing the old information first.
If you decide to begin the sentence with a dependent clause, be sure to use the comma appropriately.
