Advice on understanding poetry better.

[Magpie]

I really need some advice or guidance regarding understanding certain types of poetry. A lot of modern poetry and a lot of poetry on here is almost cryptic when I'm reading it and I really am struggling with this aspect because I really want to understand it. I know that I'm not stupid although at times I do feel that way when reading some poems. I have read a lot of poetry, in fact it is all I have read for the past two years or so. But the poetry that I love the most seems to be poetry that isn't as cryptic and doesn't have hidden meanings as much. Whitman and Ginsberg are two of the poets that I read the most and admire the most, but their poetry seems to be more realistic and therefore easier to understand; although I know that even in their poetry there are double meanings, but these I seem to get. I also love reading Sylvia Plath and most of it I get but there is a lot that I don't and then when I find explanations on the internet it seems so obvious.
I suppose I'm asking if it is a matter of practise, like cryptic crosswords get easier with practise, or is it something that you either get or don't get. It frustrates me at the moment because there are a lot of poems on here that I would like to comment on because there are people who have commented on my poems and I feel it is the respectful thing to do by commenting on their poems. And also I want to comment on as many poems as possible because I feel that it is important to contribute as much as possible.
Any advice or guidance in this area would be much appreciated. Thank you.
Mark