The TV should have HDMI ports, LAN/ WiFi and 1080p or better resolution.
Mirroring to TV (cable/WiFi):
Some tablets have a separate HDMI output for a cable connection.
Most tablets have their microUSB socket with MHL output, ready for a MHL to HDMI adapter for a cable connetion.
Nexus 7 tablet can connect via WiFi, using a HTC Media Link HD, a dongle plugged in the TV's HDMI.
Some Samsung tablets can connect via WiFi to the TV, using Samsung AllShare Cast, a device similar to the HTC dongle.
Your TV should have also DLNA ability for direct connect via WiFi without cable or dongle. DLNA does't mirroring but it does steaming media.
Harry