There could be a plethora of reasons why you're not seeing a lot of interest in your checks. On Casual and Advanced forums, I would try to have a very concrete RP idea before even putting the interest check out. You don't have to have mountains of info for an interest check, but the checks that do well tend to have a focus on what they'll be about. 

Also, take note of what's popular in the forum at the moment. For example: High School Slice of Life rps, rps based on popular anime and television shows and rps based on popular canon material tend to have more people apply for them. Also building up a reputation on the guild tends to have people that like writing with you go to your roleplay more often. 

My suggestion if you're not seeing a lot of hits on your own ideas? Take a break, look at interest checks you may be interested in, and apply for those. PM the GM about character ideas and try to show your interest; I always take people passionate about my RP, even if they don't have a rich history of detailed posts, especially over someone who's burned me in the past. Also, check out what's popular in different forums, and see about making a twist or an interesting take on that. 

That's just some ideas, anyway.