Spells take the amount of time they take to work. Magic is not like cooking where you put all the ingredients together and shove it in the oven for a certain amount of time.In magic there are many subtle variances and some not so subtle ones that can effect a spell.
Your knowledge of magic and spells is one of the first things to consider. If you are new and read a spell and used it, it is likely it will not work. This has nothing to do with the spell and everything to do with the caster.
The design and implication of the spell will also determine its effectiveness. Some spells are not going to work no matter how much you understand about magic. They just are poor quality or are set to bring about things that are not going to happen in the physical plane.
Blood has no effect on the timing or 'power' of a spell. It is a way to incorporate yourself or another directly into the work so that the effects hit the specific target.
Your actions in the physical world will also work to effect the spells ability to come to fruition. Are you working? Looking for work? Looking for additional opportunities to bring in money? Are you casting the spell and waiting for it to do the work for you? Are you talking about the spell and how it will solve your problems? Do you subconsciously think the spell will not work or have you subconsciously or consciously set up a scenario that will not allow the spell to manifest?
My basic advice to anyone who is new to magic is that spells are not the place for one to start. There are many variables that will upset a decent spell from working if one does not understand them.