Learning another language is a lifetime's task, but the process is fascinating and enjoyable. I want to emphasize the following points:

* You need to study with a textbook, not just pick up bits here and there
* Go at the pace of the textbook. Many Irish language textbooks introduce verb conjugations very slowly. Learning Irish is notorious for not going beyond the present tense for half the book, but you can only learn step by step after all.
* Discussion forums like Daltaí can help build and retain motivation. Discuss Irish and show your enthusiasm.
* Discussion forums cannot teach you a language.
* If you have only learned the present tense, don't try to form sentences using the past tense or the conditional tense: this is important because if you try to use parts of a language you haven't learned, you will just make errors, and those will be fixed in your consciousness and you will never learn properly.
* There are people on discussion forums who will encourage you to write "all in Irish" when you are in chapter 3 of a book. This is bad advice. It will have you leafing through textbooks and dictionaries and getting things wrong. No one every learned a language other than going step by step.
* Don't try to form sentences that are too advanced for you.
* Ask questions on aspects of Irish you need to know about now, while you are learning. Whether it is nasalization, the dative case or the autonomous form of the verb, there is much that you need to grasp while you are learning the language.
* To hold such grammatical discussions in Irish when you are in the early stages of the language would be self-defeating. Ignore self-promoting people who tell you you should discuss such topics in Irish or not at all. You will never learn Irish properly by listening to them.
* Help other learners with their basic queries. If they ask in English and are in chapter 2 of their textbook, resist the temptation to answer all in Irish. It may give you a wonderful feeling of superiority to do so, but will not help the learning.
* Basically, don't walk before you can run. Ignore those who urge you to do so. They do not have your best interests at heart, and are just trying to highlight their greater fluency in Irish.
* If you do these things, you will make gradual progress!

...leafing through textbooks and dictionaries and getting things wrong.
My gosh, has he been peering in my windows or what?

It's worked pretty well for me so far though, so perhaps I could offer a bit of counterpoint to the advice above (advice which is for the most part sound and will indeed result in gradual progress.)

I always found that contributing to discussions in Irish was a huge confidence booster - more than discussing the same topics in English ever would have been. I was making lots of mistakes, but I was communicating. I was being understood. I was starting to use the language, which for me is the whole point in studying it anyway. So don't feel you have to write "all in Irish" from the get-go - and for goodness' sakes don't refrain from asking a grammar question because you can't phrase it in Irish yet! - but at the same time don't shy away from writing "some in Irish" whenever you can, starting as soon as you can, even if it takes you out of your grammatical comfort zone.

In fact, make that "especially if it takes you out of your grammatical comfort zone." Stay in your comfort zone, stick to the textbook, go with what you know... this is all well and good for schoolwork, but outside of class don't be afraid to experiment a little. Getting things wrong is part of learning too! Try to do it in front of people who will correct you gently; as long as you have regular feedback, you are not at too much risk of reinforcing your mistakes. (Discussion boards are excellent for this.)

And don't forget that in a language like Irish, where native speakers are hard to find in large numbers (especially outside of Ireland), READ READ READ. Go through the book with a highlighter, looking up and filling in definitions of any words or phrases you don't know or understand.

I have been at this for many years, but I feel I've made more progress in the last month than in the whole previous two years, mostly because I've begun reading in the language.

Little things at first...An Tobar...Dúnmharú ar an Dart...now Dúnmharú sa Daingean...

The book level should basically be a little above your level, but not so much you're looking up every word. If you're consistently looking up more than 25 things per page - or if you still don't understand whole passages even AFTER looking them up - then that particular book may have to wait...