I have found that the instructions on the patterns from the 50s and 60s are much easier to understand than the ones you can buy now. Some of the current ones seem to have been written by people for whom English is their second language, plus they use some really funky ways of putting stuff together in some cases( or at least the instructions make you think HUH??? if you are an experienced seamstress).
If you can find an old Singer sewing book probably published late 40s/early 50s (big page hardback book about an inch or so thick) it gives excellent instructions on every aspect of sewing from how to make necessary alterations to a pattern to constructing the garment to darning by machine.
Barnes & Noble has one of the Singer Sewing Books in the out of print books section for $12.99 from a third party reseller. The next one listed is priced at over $50.00.
If you have any questions as you are sewing, please PM me and I will gladly answer as soon as I get back on the computer.