Well if you're green then I'm gonna assume you havent read about the correlation of lunar phases, colours, and herbs and plants. I also will assume you havent been meditating, studying mechanics of spell casting works. Also, a deepened perception of energy around you will help immensely.
If you have done all of the above you are ready to try a spell, and I dont suggest and actually warn against anything big like love spells or glomours. I do suggest on the other hand a simple good luck charm, many are on this site.
As for how long it takes to kick it in it varies spell to spell and practitioner to practitioner. Generally good luck can start 1-3 days. The more energy you can focus and the better your concentration, the better the spell works, the longer it lasts, and the faster it enacts.
Hope it helped