Recommendations For Select for Update Statments

I working on an application that generates SQL Statements with SELECT FOR UPDATE clause, these Statements cause a lock on the select rows and hence blocking other sessions,sometimes the lock stay for half an hour according to the selected data. From analzying the Locks ,i found the locking due to Logical Errors in the development of the applciation . My question from PL-SQL viewpoint is their an alternative for this mechanisem that requires a lock on the Selected rows for Update ? any recommedation to minimize this Locking ?my (Database is   10g ).

Best Wishes, 

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