Soak your lashes in a bath of hot water (I use a saucer) and leave for a minute or two. Remove with tweezers and dry with a paper towel. Any sticky residue from the last outing will be visible and will be easy to peel off.
Now you will have nice flexible lashes that are likely to stick to the corners of your eyes better.
I use Hair Extension glue instead and I find this a much more durable and long-lasting medium.
NOTE: Please do a patch test first just to make sure but it's pretty much the same as eyelash glue just a little better at sticking.