What's your personal housing situation? I ask, because, I can pretty much do just about anything around the house after 7 years of owning my own home. Obviously, I'm not talking about HVAC or electrical work here, but I've become pretty handy at putting in hardwood (bamboo) on both a slab (free floating, not glued) and upstairs where I nailed them in to the sub floor. I've also put in floor tile and a kitchen backsplash and various other things. The best resource for me was the Internet and Youtube. There are so many DIY channels on Youtube, with their own off-channel websites with step by step guides. http://www.palatinremodeling.com/top-10-diy-channels-on-youtube/
I agree that hiring things out is probably a better use of one's time as an investor than doing it yourself, but I'm of the same mind as you to try to do some of this stuff at first because I'm going to do a more traditional buy and hold pattern where I won't be able to acquire properties very rapidly, so it's not like I'd be missing out on deals by undertaking certain repairs/improvements myself.
My last caveat, I would be sure to research the permit requirements and building codes before undertaking anything more than replacing a door knob because I know Massachusetts and other northern states have very particular requirements on things you would never think you would need a permit for.