Try and do haikus. Infact, replace your usual pieces with haikus. A haiku is a 5-7-5 formula. First line is 5 syllables, 2nd line 7 syllables, 3rd line 5 syllables again. That 3 line piece would be a haiku. Nothing more. Usually. You can do 4 haikus as one piece (each haiku being a stanza) or something. There's no rules except 5-7-5. In fact, you can change the syllable formula and make it 3-6-3 or 7-10-7 or whatever. Though i'd reccomend 5-7-5 for now. This will help your structure and give you practice in compressing pieces. Less is more. The more meaning you can get out of less words the better the piece, usually. This goes for anyone. Even the most experienced do it. Haikus are a top form of poetry. Don't think i'm one of those 'everything should have structure', though i do believe ultimately most poems do have a certain structure to them. Otherwise they'd be terrible to read. But my point is that if you have a certain (even if it's loose) structure to start off with, as you go on writing them you can slowly expand and worry less about structure.