As Falcon [your mains?] you could practice trying to safely knee his shield - if you perfectly space and l-cancel a sweetspotted knee I'm pretty sure you can grab and they can't escape at all [or so I've read - someone can verify/disprove]. This is tricky, but useful to be able to do (and I think it will l-cancel it quickly enough so you can still be ready to react if they spotdodge the knee).
Alternatively if they have no projectiles, just run away, hopefully on a stage like Battlefield or Dreamland - force them into the air, because you've just taken them away from their gameplan when you're not in hitstun. If they're on a platform themselves, just SH or FH uair them from below - they'll have to come down eventually which is what you want.
Better yet, dash up as though ready to grab them, but do nothing, then grab/hit them out of the endlag of their spotdodge - spotdodge has a few vulnerability frames at the end, so you can actually punish spotdodges before they get can get their shield back up or do a roll, spotdodge, or jump. The timing is admittedly tight, but it will give you an edge versus players who spotdodge a lot.
If you have a projectile, just run away and camp them hard. The suggestions the others have given you will work well.
P.S: There should be a way to edit the title of a thread. You can probably find it and add the question mark.
