Try with excitation wavelength (laser line) which is away from the absorption band of the material under investigation. Usually higher wavelength (e.g. 785 or 830 nm) works better. Deep UV excitation can also be used but it would be complicated and high energy photons may damage sample. 

Also, adsorption of the material on the substrates such as graphene/ Au or Ag nanoparticles would be helpful in rejecting fluorescence.

An approach you could try is using a different wavelength laser line that is far away from the wavelength of your sample fluorescence.  However, different laser wavelengths will have different cross sections for phonon excitation and may make characterization and comparison to literature difficult.  Also if you are using higher energy photons you may want to consider potential sample degradation.

Try with excitation wavelength (laser line) which is away from the absorption band of the material under investigation. Usually higher wavelength (e.g. 785 or 830 nm) works better. Deep UV excitation can also be used but it would be complicated and high energy photons may damage sample. 

Also, adsorption of the material on the substrates such as graphene/ Au or Ag nanoparticles would be helpful in rejecting fluorescence.

It will be very helpful if you know the absorption band and then you can choose the right excitation energy (Laser wavelength). As Rekha Gautam wrote above, laser energy lower than the absorption band should work. If possible, try to choose a higher wavelength laser source, such as, 785 nm or higher. Depending on the position of the absorption band, 633 nm laser also may work.

All of the comments above are right.

Sometimes it is also possible to photobleach the fluoresence. Irradiate your sample with the laser and see if the fluorescence goes down. Just keep in mind that it might  burn your sample.

Good luck.

You can also try to use some quenching for fluorescence. For example, adding of plasmon resonant metallic nanoparticles can both to quench the fluorescence and to increase Raman signal by SERS.

There are some methods to observe Raman bands of fluorescent materials:

1) using exciting laser lines with long wavelengths (in the spectral region of the red or infrared radiation) one can prevent electronic absorption and thus fluorescence; however, the intensity of Raman scattering results lower than that obtained with excitation laser lines with shorter wavelengths (for example, in the blue or green light region);

2) in the region of anti-Stokes scattering, fluorescence does not occur and therefore it is  possible to observe Raman bands (especially those with minor Raman shifts), although of much lower intensities than those of the corresponding Raman bands in the region of Stokes scattering;

3) by strong interaction with Ag or Au nanoparticles it is possible to observe Raman bands by means of the SERS (surface-enhanced Raman scattering) effect, with marked fluorescence quenching.

However, failing to provide different exciting laser lines nor appropriate SERS substrates, it is possible to mitigate the fluorescence emission, favoring non-radiative decay from the excited electronic state of the sample molecules, for heat exchange with surrounding molecules, for example by finely mixing fluorescent solid samples with KBr powder.