Graphene is a monolayer of carbon atoms which possesses delocalized π electrons and a good electrical conductivity. Good electrical conductivity with a large specific surface area opens up the possibility of its application in electrochemical energy storage devices. Physical and chemical properties of graphene as well as its sheet size depend on the synthesis method. In this paper, graphene was chemically synthesized using various graphite forms as precursors. In the first step graphene oxide (GO) was obtained and it was used for further synthesis of reduced graphene oxide (rGO). The reduction of graphene oxide is a crucial step in which it is necessary to remove a variety of oxygen functional groups bonded to the graphene structure. It is desirable to achieve a high degree of reduction and to ensure electron conductivity with preventing the graphene agglomeration. In this paper the influence of the degree of reduction on the capacitive properties of the obtained rGO was studied in details. Additionaly, the possibility of using olive leaf extract (ELM) and tin (II) chloride as ecologically acceptable reducing agents was studied. Structural and morphological characteristics of the obtained materials were determined by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction analysis (XRD), Fouirer-transformed infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). By using cyclic voltammetry and electrochemical impedance spectroscopy (EIS) methods it was shown that the all prepared materials exibited good capacitive properties in 0,5 mol dm^-3 Na2SO4 solution. The prepared materials were used to asemble supercapacitors that were tested by cyclic voltammetry and EIS methods. The stability of the supercapacitors was determined by charging/discharging at constant current during 1000 cycles. In order to improve its capacitive properties, GO is modified by the two different aromatic amines: aniline and o-phenylenediamine. They can contribute to the pseudo-capacitive effects and increase the overall capacitance of the base materials. Modification conditions and physicochemical properties of the obtained materials were studied in details.