Hi,
The way to make the pdf files smaller is to split the PDF files into small number of files, i.e select the page from the large PDF file and split the selected page into new PDF file.
To split the large PDF files you should go for a third party tool like PDF split tool. This tool works for large PDF files and split the PDF files into small PDF files by giving page range as the input to the tool and output will be the PDF file containing the selected page range. There are n number of PDF split tools in the market, but i can suggest you a best PDF tool which i choose from the bundle of the PDF split tools.I use this tool oftenly and my friends and colleagues also use this tool in there daily routine.They are very please from this tool.
You can use
SysInfoTools PDF Split. Try this tool and you will surely satisfy with its features and will surely be able to make your pdf files smaller.
http://www.sysinfotools.com/recovery/pdf-split.html