I think it's great you are interested in becoming a vegan! Here's what I experienced: Vegan foods often have less calories than animal products, therefore you should make sure your plate is a bit fuller when eating plant based. It's also helpful to eat a good amount of whole grain carbohydrates and lots of legumes, so that you're full.
Of course, the hardest part is to overcome our non-vegan habits and cravings. But just try out some alternatives and slowly replace your non-vegan meals for vegan versions you actually really like. There are plenty of awesome recipes on the internet, including Steemit :) Some of them you might not like, but then just try another one! Over time, you'll get used to the new foods and crave animal products less.
I also highly recommend you to join the Challenge 22. You'll get assigned a mentor to help you transition and support you in your journey towards veganism.
Of course, the transition is a process - and every person experiences it differently. Remember: every small step you take is a step in the right direction!