If you're not proficient on starts & finishes where there's an air gap at each end, you can often tack a small tab at each end on which you can then start & finish, just grind off the tabs after completing the weld. The main weld then looks consistent and even.

If your hand is a bit shaky with a long new electrode, hold near the bottom of the electrode with your (free) gloved left hand to strike, then gradually move that hand up the electrode as it burns down, withdrawing it completely when you feel comfortable and steady.