Is exchange link still working now?
if yes, How to exchange backlinks safely to get higher keyword position on SERPs?
The best ways to exchange safe backlinsk to your blog is to find a good link partner..
What the good link partners means...?
The relevant niche to your blog and high quality article for exchange backlinks.
The best way to find to partner blog is Google, you can try relevant keyword that you want to rank. Then find some quality blog with quality article...
What you should check are,
Domain authority, what is the score of their domain and I may recommend from 25+ score
Page Authority, it is important to pull your keyword ranks if you got from high authority page.
Social signal, how many people who shared the content...
What the strategies to get exchange...?
Please do not send those blog owner of the link exchange proposal, but you need to interact and build relationship with them first...
You should find their social profiles and connect with them via Facebook or Twitter, or whatever you prefer..
You must spend your time to build relationship with those blog owner through comment and private message to them, but whatever you use please keep in mind. You just want them to be friends...
You also subscribed their blog' newsletter for upcoming topic, and then comment on their article. It's the best ways for build relationship between readers and blogger.
Finally, you could send them link partner proposal anytime you thing that you're close to them...
I hope it helps..