Tips to keep things spicy!!!

So the prob I'm having is at the moment we are timing sex for ovulation and even then we don't do it every day so this month I'm making it my mission that my other half and I BD every other day throughout after AF has finished showing her ugly face!!! And as often as poss during fertile cycle but any tips to keep things spicy!!! We're often so tired from work during the week that all we want to do is sleep!!!!