Pick a song you really really love which fits realistically within your short term future refreshed or newly acquired skills remit so it is an actually attainable objective.

Then attack it with the gusto which should come easy for any song with which you are truly enamoured. Accompanied by the necessary repetitive practice, perseverance and determination, you'll make progress fast which reinforces confidence and reinvigorates motivation, which in turn provide all important medium and longer term momentum.