by making it interesting .. .
Stupid answer but true. The best writers can take an info dump and make it interesting to read.
Why should a flashback be boring? Put the facts in an interesting context. Flesh them out with drama and conflict, a micro subplot.
If you need to explain something about a dinosaur DNA or computer viruses, use analogy, conflict, humor, whatever. Like the stuff a teacher would come up with to get the point across.
Story telling is well, always story telling. If you've got to state some hard dry facts, mix in some story telling. Do it right and the reader won't even know they're being fed information.
I guess it's like giving your cat his medicine. You can powder it, and mix it into his normal meal, a bit or a time. Or you put it in as a lump in something he really likes. Or do both, and he'll never know.