Yes a much discussed topic but without wasting your time here we go:-
1. Keep your hands on your cellphone and pick up the phone every time she calls. Many people have said finish todays work today otherwise it keeps piling up. This phone call from your wife you dont want to keep pending.
2. LIKE all her vacations photos on Facebook/Instagram! Make sure you know the reasons for liking the post as well.
3. WhatsApp her now and then with love messages! They dont cost as earlier even if you are out of country.