It is a well documented fact that children learn better with information is provided across more than one of their senses (touch, taste, vision, hearing, balance). There are many inexpensive multi-sensory experiences you can use at home to work on learning to write letters and/or learning to spell.
Put some shaving cream on a cooking sheet with raised sides. Let the child “write” a letter with their finger, then “erase” with their hand and start over. If you have a child that still puts fingers in their mouth, this may be better done with something edible like whipped cream or pudding.
Practice making letters with pipe cleaners or “wiki-stix”. These bendable items are perfect for early letter making.
Practicing writing letters outside on a driveway or sidewalk with wide “sidewalk chalk” is a great multisensory experience.
Fill a small bucket with water and get a large paintbrush. Let your child “paint” letters on a driveway, sidewalk, or even the side of a building.
Get a set of letter stencils and cut letters out of coarse sandpaper. Let your child trace their finger over these letters to help learn their shapes.