Really early on in my transition, when I couldn't order anything because I hadn't come out, didn't have a paypal account and therefore couldn't order anything I used a woman's silhouettes type body shaper thing. it was meant to go over ones tummy to help make you look thinner, kind of had the look of a bustle that was missing the top (breast) half. This worked for me for about 5-6 months till I got the chance to upgrade thanks to a friend who was over 18 and could order it for me and have it shipped to her place.
I'm not sure where you live exactly, but a lot of online stores will accept a pre-paid VISA (the kind you can buy at a gas store). Then all you need is a friend who will let you ship something to their house. Tell them you are buying a gift for one of your parents but don't want them to know about it if you aren't out to them. That can work.
Depending on your bust size, if you have a smaller chest i've heard layering tight t-shirts can help, or using tight sports bras with tight t-shirts over top. If your bigger chested like me, picking up a body fat compression shirt like I mentioned earlier is your best bet, coupled with a baggy sweater.
With regards to a packer, I had an FTM friend who used a condom filled with lube, I've also heard of men using rolled up socks. I'm not very dyphoric with regards to my groin so I just waited till I can out to my family to order myself a packer.
Short hair will help you pass the most I think (after dealing with your chest) I definitely felt way more confident when I got my first men's haircut, and I definitely looked more male. Try shopping in the men's section when it comes to clothes. Men's pants fit differently then woman's, so not only will you feel better but you'll also help yourself to pass.
Also try studying men's subtle non-verbal behaviors. How do more men sit? How do they talk? How do they stand, walk, run? If you can begin to mimic those behaviors, that will also aid you. Mostly though it's about doing what makes you more confident.