My blog has 11 Domain Authority on SEMrush and I am getting around 1000 clicks in a month. Do I need to focus on backlinks to grow my traffic? If yes, then please share some best strategies for link building.
I would say good job, and yes to both, you should be focusing on both..
How many clicks you get is great knowledge, where you are ranking and the monthly search volumes for your keywords would be better knowledge yet in order to determine how much improvement you need or is possible.
could very well be that you happen to be targeting a keyword that has an exceptionally high volume of search and maybe you're not even on the first page but could be seeing 100 times that much traffic with a little work.
Keep in mind, a thousand visits a day is a drop in the bucket, a holistic approach is always best, so yes focus on building links, yes focus on getting traffic from social and other sources as well.
Also, do you not rely on da alone as a source of gaging the SEO quality of your site or any others in and of itself, it is very flawed and based on educated guesses, no better than you or I could make they just have crawlers with a big enough budget to have found more of your backlinks than you or I could, but nowhere near what Google has nor are they pretty to Google's algorithms anymore than you or I would have access to.