The main route for hiking is the Ulster Way that is designed and widely publicised with hikers in mind. My advice is to purchase a guide that details the walks including distances and expected walk time.
Waymarked Walks gives loads of useful information on local walks.
Tough waterproof boots
I enjoy the occasional hike and thought it may be useful to some if they knew what they were missing.
Walk2 – Giant’s Causeway to Ballintoy Harbor
Walk3 – Glenariff Park Camping
Walk 4 – Knocklayde Mountain
Walk 5 – Lurigethan Mountain
Walk 6 – Moyle Way Stage 1
Walk 7 – Moyle Way Stage 2
More info on this subject to come…