Hi,

That's pretty good - the only thing really that needs attention is that unless you are of the continental European persuasion, the Helm shown is that of a Peer. The Helm should be that of and Esquire/Gentleman which is plain steel normally shown in threequarter-facing to full-facing dexter (the same side of the shield as the lions). With a surname like Griffiths, I would assume that the heraldic tradition being followed would be that of the UK's College of Arms.

The mantling is usually of the first metal and first colour memtioned in the blazon which in your case would be Argent and Gules (for the arms on the dexter side).

<<Per pale gules and or, three lions passant argent, a feather, quill downwards, gules, flighted sable. Right? >>
Not quite - 'Per pale dexter Gules three Lions passant Argent sinister Or a Feather point downwards quilled Gules flighted per Chevron inverted Sable and Gules' would be my interpretation of those arms.

As for the crest - normally [but not always] issuing from a torse of the same tinctures as the mantling. I'll leave the remainder of the crest as you're about to change it. How about a Lion sejant affronte Argent holding in the dexter claw a Feather [yyy] xxxx and the sinister grasping the shaft of an Anchor xxxx - with the xxxx being the tincture of your choice and the [yyy] for a description of the feather if not of one tincture. However, that would be appropriate for an affronte facing helm but not for a threequarter or sideways facing helm.

Unless a Scottish armorial achievement, the motto goes in a scroll below the shield and the surname is not shown anywhere. If following the Scottish tradition, the motto goes above the shield and the crie-de-guerre goes below.

That's a pretty good effort for a 'beginner' - glad to see that you've signed up as an AAH member - we'll try and enlarge your heraldic knowledge and artistic skills.
Ciao for now -