I'm a big fan of soft hackles early in the year. For gills and crappie it's usually an olive soft hackle in a 12 or 14. For bass I'll bump up to an 8 and tie a somewhat bulkier than standard body to get their attention. I fish them unweighted this time of year so they sink verrry slooowwwwly. Soft hackle have a lot of movement even with a super slow retrieve and that slow retrieve is the key because cold fish are slow fish, they won't chase food like they will later in the Spring, but if you bring it by them slow enough, they won't pass up the opportunity.
If it swims and eats, it'll eat a fly.