Good for you on deciding to finally sew up that vintage pattern! Here are a few things you may want to take into consideration:
- Is the vintage sewing pattern printed or unprinted?
This might only be important to a beginner sewer, to someone new to working with vintage sewing patterns or to someone who doesn’t like working with unprinted sewing patterns. A beginner may find it easier to work with a vintage sewing pattern that contains printed pattern markings.
- Is the pattern complete?
For obvious reasons, you’ll want a complete sewing pattern. But believe it or not a few missing pieces (dependent on which pieces) aren’t necessarily a big deal. Facings, tie-ends and other small pattern pieces are easily made from scratch or modeled from other pattern pieces on hand with very little difficulty.
- How many pieces are included in the pattern?
If you’re the type of sewer who prefers “fast’ projects or very easy designs (a beginner or someone new to vintage sewing) you might want to pick a pattern that has fewer pattern pieces. But that’s subjective. For me, modern day patterns have way too many instructions and patterns pieces-making sewing time consuming and overly complicated when it need not be so.
Information overkill. Others appreciate the detail.
- Are the instructions present?
If you’re good enough, I guess you could construct an entire garment using only available pattern pieces. Otherwise, you’ll want to know if the instruction sheet is present and legible.
- Who’s the maker of the pattern? If known.
I like working with Anne Adam’s mail order patterns. I believe the designs come out “tighter” and better constructed and instructions are adequate enough to zip quickly through a sewing project without getting a mini-headache. But that’s me. Someone else (you) might be partial to another pattern manufacturer for the same or different reasons.
- Is the pattern envelope present and legible?
Pattern envelopes contain valuable information related to the construction of the garment.
- What condition are the pattern pieces in?
Expect vintage sewing pattern pieces not to always be in mint condition. You might find pins, needles, glue, tape ect…it’s pretty normal. Most vintage sewing patterns were actually used. Can you believe it? 
Just make sure the pattern pieces aren’t in such a state you’re unable to use them in your sewing project.
- How to determine your size in a vintage sewing pattern
I know, that’s only 8…I need another tip…
Sewing Pattern Portal
For another tip to consider, how about the fact that if the pattern envelope is missing, the pattern was likely to be a discard (out of print, no longer in the catalogue) – I used to work in a fabric emporium and when patterns were discarded (ie deleted from the catalogue) we only had to send back the envelopes. We were allowed to take any of the inner bits for ourselves, free of charge. This is of interest only because if someone is trying to sell an envelope-free pattern for a substantial sum, you have a right to query it as they probably got it for free in the first place…
Wow! Very nice bite of history. Not concerned about whether the seller originally acquired the pattern free of charge in the first place, but I know of someone who has a cabinet of sewing patterns from the 60s-all without pattern envelopes. I believe you just solved a mystery for us! Thanks so much!