So i would just like to clarify some things, so i know that doing a spell on a certain moon phase, in a cemetary and adding candles makes a spell more potent but is there anything else i can use? Like i have heard blood works also
The strength of the spell doesn't really come from the tools you use, it comes from the intention you put into it. Adding tons of herbs and crystals won't necessarily make it more powerful if you don't put your intention behind it. Although it can add a kick to it if you're in the right mindset.
That being said, yes, blood is powerful, but you need to evaluate what you're using your spell for, depending on the intention, blood can be suitable or maybe unnecessary. I don't really work with blood so I can't help much on that.
The main thing to bear in mind is that working magic is about forming a direct mental connection between your actions and a desired intent or outcome. Symbols themselves come in a -huge- variety of shapes sizes values and meanings. And often many ideas traits or actions can have many different things that can act as symbols.
The trick is in collecting a set of symbols and symbolic actions that give a sense of gravitas or validity to your personal actions when related to influencing the desired ones. You want symbols that are related to the goal of your working. You want them to have a personal meaning. That meaning allows you to mentally connect action with outcome.
For example, a graveyard is a good place to go as a symbol of connection to one's ancestors, the deceased in general, or the overall transient nature of life. So it is naturally easy to associate performing a spell in a graveyard to those influences. However graveyards are usually not associated with ideas of fertility, or celebration, or abundance. So it would not lend much power to, say, a spell for a favorable job interview.
It isn't about the relative 'strength' of any given symbol, but how strongly it relates to you and your intent.