No. 1 is the amount of transactions between buyers and different people. For example if you have 100 BTC you want for $ 1, but someone with 100 BTC want to sell for $ 2, the value it will increase so.
Secondly because of the rare bitcoin copper, and the need to use BTC for various purposes so many people need BTC that makes the BTC increase.
Third, by speculation, those who have money to inject money into the market and use FOMO tactics to entice more and more people into the market, the price will be pushed up.
There are many other factors, but only focus on the three main good.
It is about how people using bitcoin manages their bitcoins. As people do panic selling when bitcoin's price drops, the tendency is it will continue dropping down. As far as I know, as bitcoin's volume increases, as many bitcoin is produced, the lower the price of it, correct me if I am wrong.