More then likely, if it's not the way you apply them, it's the glue adhesive you are using, One customer sent us labels before where when the label was applied to a hot bottle, bubbles formed on the label, due to the glue make up.
copied from Hot sauce making for an Uber newbie...Wipe the top if necessary. Screw on the cap and immediately invert the bottle. Leave the bottle inverted for at least 5 minutes. This allows the hot product to come in contact with the cap and to kill all the nasties.
+1 apply while warm or use an added adhesive that requires curing time. I really like the glue adhesive from glue guns. I heat up 20-25 sticks in an old sauce pan on low then smear it on while rolling bottle over label, if thats too time consuming or you prefer self adhesive labels then simply spray your bottle with a mild dish soap solution and roll the label on. it will allow you to squeeze out the air bubbles and will cure in 30 minutes
I'm applying my labels by hand - so far, 3/4 of them end up with bubbles, which I try and push out with my thumb nail, with varying degrees of success.
Any tips or techniques?
They're 4 x 3 labels on a 12 oz bottle
+1 for what ^ said.
It can also help to lay the bottle on a folded dishtowel to prevent it from rolling while you are trying to position the label.
Also, if using inkjet labels, there are clear sealer sprays you can use to help keep the labels from smearing. Laser prints are better, though.