How can I raise my bathroom vanity?

Hey. Firstly I would check if the plumbing in your vanity would allow for that. If it doesn't, you can always add tiles to the back splash area to increase it a bit

It is a big job. First you need to remove the mirror. Then disconnect the plumbing. Then remove the cabinet. Now you need to relocate the plumbing to accommodate the new height and put it all back together. Get help if this is your first major DIY project as it is not as simple as it seems.

Depending on the cabinet/vanity style you can usually separate the base from the top and add filler between them to get the added height. Can be as basis as framing up with 2 x 4 or more ornate using any of the decorative moldings. Still requires the basic plumbing work .

Naomie is right. You need to remove the mirror. Disconnect the plumbing to the sink. Move the whole cabinet. Check to see if it screwed to the wall. Build a base same size as the cabinet the height that you want. Lay the base where the cabinet was. Put a bead of clear silicone around the perimeter of the base top. Place the cabinet on the base. Wipe off any caulk that squeezed out. You'll need new longer hot and cold water lines and P trap extensions to reconnect the sink. Paint or stain the base same as cabinet. Reinstall the mirror.