1. Use flash cards.
Flash-card technology is still better than the most expensive educational computer software that you can buy. It is the quickest way to get just the repetition you need of the words you need to remember. It is tried and true. And it is also inexpensive.
Using index cards or a pack of blank business cards, write the target words and phrases on the cards, putting one language on the front and the other on the back. As you review the words, proceeding through the pack, separate the words into two piles: those you understand immediately, and those you do not. Keep going through the yet-unlearned words until you achieve a mastery of them.

2. Think of cognates and usages.
Think of words directly related to the word in question (cognates) or of common phrases that use the word. For example, Semper fidelis ("Always faithful.") is the motto of the army. Using this method, you may actually have already taken the first step to learning these words.

3. Visualize and vocalize.
Focus on an image that a word represents or suggests as you say it aloud.

4. Use the diglot weave.
Insert foreign words into your sentences until you get their meanings quickly. For example: semper in English means always, so repeat to yourself several sentences like: I will semper have trouble with vocabulary unless I learn it. Romeo told Juliet, "I will love you semper. Two and two semper make four-SEMPER! It semper gets cold here in the winter. The sun semper rises in the east. Semper in September the Autumn semester commences.

5. Practice the key-word, key-sound or key-letter technique.
Think of a word (called the key-word) based on the first (or very prominent) syllable of the foreign word (or on the sound of the whole word) and then make up a story or an image involving both this key-word and the meaning of the original word. Stories are easier to remember than individual words, so this key-word will get you back to the foreign word if you are going from your language to the other one.
For example, semper might suggest the sound of the word simmer, and vice-versa. Think of a volcano that is

ALWAYS "SIMMERING." Hold that image. To fix the association of always and simmering you might make up a story about visiting Hawaii or Sicily and not being able to see a volcano because it always seems too active. You remember being disappointed, but not willing to take the risk of the trip.
An even better method would be going directly from a syllable of the word to the connecting image. To remember that Boletus means mushroom in Latin, take the first syllable and think of a bowl that is a mushroom cap turned upside down. Here, there is no need for a story. The striking image is enough to get you to the first syllable -- and the content -- of the Latin word.
In the example of the diglot-weave above, the sound of the word September helps you remember the similar sound semper. The phrase "semper in September" has the sort of ring that might remain with you. Or you might think of a synonymous meaning that gets you to the word, e.g., ever has two short e-sounds, just like semper.
You can more easily remember that tamen means nevertheless in Latin by noticing that the last two letters backwards start to spell NE-vertheless: tam-EN. Likewise, nupER means REcently.

6. Read, write, and recite phrases.
Discover, create, and review many different phrases using the word to be remembered. This helps you to process the word deeply in your memory by building more mental bridges to the meanings. This helps you to recall the word faster.

7. Repeat, repeat, and repeat again.
Especially for memorizing important parts and forms of words, sometimes only "brute" repetition will help you remember certain hard-to-retain vocabulary. Frequent vocal repetition impresses the forms on your "mental ear." This auditory dimension will help you recognize and recall the words later.

8. Read freely and abundantly.
We can increase our vocabulary easily through free voluntary reading. However some linguists say that we must first have acquired about 3000 to 5000 word-families, so that we will be able to know enough of the context to begin to construct accurate meanings for the words that we do not yet know.
We hope the tips above will help you accomplish your learning goals quicker and we wish you great success in learning your new language.