Definitely plan something fun every now and then, focus on exciting goals, and give yourself something to look forward to. For example if you want to cloth diaper allow yourself to get a new diaper or accessory every month or whatever so that you're both building your stash for your future baby and giving yourself a short term exciting thing to look forward to in the mail. If it makes you feel uncomfortable buying baby things before pregnancy then do a monthly subscription service that has nothing to do with babies and everything to do with your hobbies and interests. For example I have a Fragrant Jewels Inner Circle membership so I get a candle and a bath bomb every month, I always look forward to them coming in mail! Or you can do both small baby purchases and a subscription service if you want to.
When you're feeling extra broody and short term goals aren't helping, give yourself a pep talk. Remind yourself when your TTC date is, that this day will eventually arrive and how worth the wait your baby will be.
If you have to remind yourself how much you love alcohol/sushi/hot dogs/whatever food or activity you love and can't eat or do while pregnant and treat yourself to whatever it is while you can.
I know it's hard to picture it if you've never been pregnant but reminding myself how awful morning sickness was, how uncomfortable the 3rd Trimester was, how painful labor and childbirth was, how much breastfeeding hurt in the first few weeks after birth, and how little sleep I got in the newborn days also really helps alleviate my broodiness temporarily when necessary.