Yes, it is, and it takes time... remember “Whenever you get frustrated with yourself, remember that it takes 13 hours to build a Toyota and six months to build a Rolls-Royce.”
This is a numbers game, if you check out 100 properties and find 10 to make offers on, you might get 1 accepted... that means you need to get busy and work hard... also remember that the 70% rule is a rule of thumb and not an accurate measure in all cases... for instance on a property ARV less than 100k you need to make it 60% or less... I know that on deals over 200k I can get away with 80% unless there are some extreme rehab costs needed.
Just keep looking at properties and eventually you will find the diamond you are looking for... you might also consider finding a wholesaler in your area to buy from, or to double wholesale from... depending on the spreads, just try not to make them too thin for the poor rehabbers!
If you want an excuse to not do this, there are many... if you want to find a way to succeed at this, start with "Why?" and when you know why you are doing it, ask "How can I do this?" instead of finding reasons you cannot do it.
~James