Truncation Error in SSIS Package.. Need help

Question

I always gets truncation error in destination in my package. Sometimes data types do not match and sometimes size of data.
To fix it, I use the advanced editor and in the tab "Input and output properties",
I change the data type or size in external columns to match them with input columns accordingly.
But I doubt if it is the right way to handle such error. Or data convertion tools is the best way to handle such errors.
Right now i have such errors in all over my package. Please advice me..