Hi. I've been studing Spanish for some years now and this is what I think about the tenses.
1. Start with preesens. Practice the idea of regular verbs. Practice the most common irregulars and other than just memorizing them, find the regularities in the irregulars.
2.For the English imperfect you have imperfecto de indicativo and preterito de indicativo in Spanish. Both are VERY important, but the first one has only 3 irregular verbs! So you need to work more on preterito. If you don't already speak on Romance language(Portuguese, France etc), you need to work a lot on when to use imperfecto and when to use preterito.
3. perfecto and pluscvamperfecto(de indicativo) are easy, since they work with auxiliar verb(haber) as in English. So you only have to learn Haber and handfull of irregular participios as muerto, hecho, roto, puesto, dicho and abierto. You use them pretty much as in English, or you can at least think like that in the beginning. Que has dicho, often means also: What did you just say? So perfecto can be used in something that just happened.
4. First you can forget future tense, since everybody uses ir + a + infinitivo anyway. (vamos a comer) in literature and writing "real future" is used more and it is more accurately future tense than the "easy future", than can mean also now. Future and condicional are still easy, since they have the same list of irregulars and there aren't that many.
5. Never believe, if someone says that subjunctive is not important to speak Spanish. It is! It's not the first one to practice though. You should still start thinking about the presente de subjunctivo, and especially when it is used and when not. Same rules apply to other tenses of subjunctivo. It's a complex system, but once you get the idea, you learn to use it fast. And there are not that many irregularities, since the same changes happen in subjunctive as often in preesens.
So my list for you is: -PRESENTE DE INDICATIVO
-IMPERFECTO DE INDICATIVO(only 3 irregulars!)
-PRETÉRITO (Most common verb to use when telling a story.)
Once you get the idea of those, you can rapidly learn these:
-PERFECTO DE INDICATIVO (with auxiliar verb being same with every verb, you only need to practice some irregular paricipios.)
-PLUSCUAMPERFECTO DE INDICATIVO (just as easy as perfecto.)
After those you should practice:
PRESENTE DE SUBJUNCTIVO (you need it for subjunctive, but also you need it for imperatives, since all the others but you and vosotros forms of imperatives are made with presente de subjunctive and EVERY negative imperative as well.)
You can speak perfect Spanish without the future tense, so learn it later. Just say: Voy a aprenderlo más tarde.
Good luck with your studing.