Have at look at the French grammar section of this web site-- there's a reasonable amount on verbs, include one or two exercises.
One problem with verbs is that the traditional analysis makes them look much more complicated than they really are. Remember, for example:
- you don't really need to learn the past historic beyond occasional forms such as "fut" (from être)
- the subjunctive form is practically always based on the 'ils/elles' form of the present tense (and practically always sounds identical)
- the imperfect form is practically always based on the 'nous' form of the present tense
- practically all of the time, the singular forms of a given verb sound identical-- the rest is just spelling complications
- try to see and remember patterns that apply across the board (e.g. the "tu" form generally always ends in -s or -x; the "ils" form always ends in -nt).
As with many aspects of language learning, the approach that's effective for you also depends on what kind of learner you are-- and that's something only you can really decide:
- if you're more of an "analytic" learner-- i.e. you're good at spotting rules and applying them-- then bear in mind that with most irregular verbs, what's actually irregular can be condensed down to a very small number of irregular verb patterns;
- on the other hand, if you have trouble actually applying such patterns and prefer to see things "spelled out", then see the French verb widget, and consider something like Barron's 501 French Verbs or Bescherelle La Conjugaison pour tous.
Oh, and see an article I wrote a couple of years ago on the spelling of -eter and -eler verbs: sometimes, the answer to what is the "correct" written form of a verb is "nobody knows"...