First, you're going to have to state what you want to happen. Do you need a Job, Do you need Money?, Do you want to Attract and new Lover? Just be Specific on what you want the Spell to do, if you're not Clear on your Intention for the Spell then there is a Highly chance your Spell isn't going to Work. You might want to Relax abit before you do this, get a Bathe, Meditate, do what Relaxes your Mind. You don't want to set your intention when you have thoughts running threw your mind.
Materials Now that you have set your Intention for the Spell.... You now need to think what Materials you need for the Spell, it is entirely upto you. You can use Candles, Herbs, Stones, Crystals, incense and so on. It is best to choose Mterials that have a connection to your intention. What I mean by that is... You mainly have a red candle when casting a love spell.
Timing Timing is really important... In many Traditions the Moon Phase is very crucial, while with others it's not even Significant. Positive outcomes are usually casted on a Waning Moon. Anything Negative is best to cast on a Waning Phase, Really it depends.. Some people only do Spells on certain day, for example you may wake up one morning and feel that today feels like the best day to cast your spell. If you're a very confident practitionar you may want to cast a spell without even timing it. To me, it really depends on the idividual.
How you are Going To Cast it are you going to chant the spell? Call upon the gods you work with... Just do whatever you thinks best, you don't have to say anything verbally, you can do it like a wish, visualize your spell working then that's it. It doesn't matter how you cast it just as long as you have done it. You can make it into a poem, you can do anything.
Put all of that together and you should be fine