You can't write good poetry unless you read good poetry

If you are a poet, reading poetry should be something you want to do, sometimes it should be pleasure. You won't be taken seriously

as a poet if you don't read poetry.

It's more than useful to be familiar with the poetry of the past, good poetry has been written throughout the ages and an understanding

of the ways in which poetry has developed will serve you well, but you should certainly read contemporary poetry. c/f Staying Alive

Reading poetry is one of the best and most inspiring ways to learn about the art and craft of writing poetry.

Try to read a poem every day.

A good anthology is really useful. Staying Alive and Being Alive, both published by Bloodaxe Books, are good places to start.

If you don't want to buy them then your library should have copies or be able to order them.

Single poems can also be found on the web, see for example: Poetry Archive; The Poetry Library ; The Poetry Society.

Single Poet Collections offer a deeper, and in many ways more satisfying, engagement with the poetry of an individual poet. 

Simon Armitage has written an irreverent guide for poetry readers it can be found on the Poetry Book Society website here

Also recommended:  

52 Ways of Looking at a Poem by Ruth Padel

and

The Poem and the Journey by Ruth Padel