Better education on contraception use would be a big one...
A substantial portion of women who get abortions do so due to contraception failure due to improper use.
36.7% to be exact.
As would making contraception options either affordable, or no-cost.
However, the "people just need to be abstinent and this won't happen" has proven to be nothing more than drivel for the past 30 years, and hasn't yielded any sort of positive results when looking at the big picture.
The real question to answer, with regards to abortion isn't "how do we stop people from having sex to stop pregnancies?" That's a fantasy...people will continue to have sex, just like people will continue to eat bad food.
The real question is, "How, when a woman is faced with an unplanned pregnancy, do we make her feel like she has options, and can tackle this challenge?"
...and the answer to that question is rather simple, however, many folks in the pro-life camp often choose to back the politicians that miscategorize that answer as "that's evil socialism, and we shouldn't have to pay for that!"
If conservatives in the pro-life camp really want to reduce the number of abortions (which they claim is the goal, right?), they need to back of their position of wanting to have their cake and eat it too. They want to reduce abortions, but they only want to consider the reduction methods that fit neatly into their ideological/religious moral standards. Meaning, they'll oppose social safety nets, they'll oppose taxpayer funded contraception programs, they'll oppose measures that would actually make the most expensive costs associated with parents (IE: education and healthcare) more manageable. They only want to consider "just stop having sex" as a solution.
Contrary to what they think "you just have to suck it up and raise this kid as a single mom on a low income because we don't think you should've had sex in the first place, and this is your penitence for doing so" isn't a very compelling argument...
When pro-life conservatives start becoming more receptive to social safety nets, then I'll believe they want to solve that problem...